You Shall Have No Other Gods:
The Book of Exodus

Lesson 4 God Sends Aaron to Help Moses
the book of Exodus 4:1–31

Revised Standard Version Catholic Edition (RSVCE)*
New American Bible Revised Edition (NABRE)*
Catechism of the Catholic Church
ex libris (in our library)
glossary for the book of Exodus
cross references in the book of Exodus
next lesson: Pharaoh Does Not Know the LORD

This material coordinates with Lesson 4 on pages 20–24 in the study book You Shall Have No Other Gods: The Book of Exodus.

And God spoke all these words, saying, ‘I am the LORD your God, who brought you out of the land of Egypt, out of the house of bondage. You shall have no other gods before me. You shall not make for yourself a graven image, or any likeness of anything that is in heaven above, or that is in the earth beneath, or that is in the water under the earth; you shall not bow down to them or serve them; for I the LORD your God am a jealous God, visiting the iniquity of the fathers upon the children to the third and the fourth generation of those who hate me, but showing mercy to thousands of those who love me and keep my commandments.”—the book of Exodus 20:1–6

welcome to our in-depth study of the book of Exodus
We invite interested groups and individuals to check out the sample first lesson from this 28-lesson Turning to God’s Word Catholic Bible study. These online study pages link to our free lesson video overviews, as well as to a glossary and cross references in the biblical text. Other study aids include maps, additional commentary, and prayers based on the primary Scripture in each lesson. You Shall Have No Other Gods: The Book of Exodus has been granted an imprimatur and can be purchased from our website shop. If you have a Bible-related question or comment, click on one of the “ask us your question” or “what do you think” buttons on any online study page.

open with prayer
It’s always wise to begin any Bible study with prayer, whether reading the Scriptures alone or meeting with others in a discussion group. You can pray using your own words or use one of the opening prayers on our website. We especially like the following:

Lord Jesus, you promised to send your Holy Spirit to teach us all things.
As we read and study your word today,
allow it to touch our hearts and change our lives. Amen.

let’s review—the book of Exodus 3:1–22
Lesson 3 God Reveals His Name: ‘I AM WHO I AM’ describes one of the more significant events in Scripture in which the LORD tells his name to Moses. This occurs after Moses has been living for some time in Midian, away from Egyptian and Hebrew influences. Prior to this time, Moses hasn’t seemed to be personally acquainted with God, who introduces himself as the God of Moses’ father and “the God of Abraham, the God of Isaac, and the God of Jacob.” The LORD calls Moses to go to Pharaoh and ask that the Israelites be allowed to leave Egypt. When Moses demurs, God promises him a sign that won’t be obvious until Moses has done what the LORD is asking. It’s after this that Moses asks God’s name and is told the LORD is “I AM WHO I AM.” God’s promise is based on his covenant with Abraham, Isaac, and Jacob to give their descendants the land of Canaan. The LORD also describes some of what Moses can expect to see happen when he goes to Egypt—that Pharaoh will refuse to comply with Moses’ and Aaron’s request until compelled by God to let the Israelites leave, and that when they go, the Egyptians first will give the Hebrew women who ask silver and gold jewelry and clothing.

Moses’ life shows us a model for prayer (40:53)
The fourth chapter in the book of Exodus records Moses’ response to God’s plan to free the Israelites from bondage in Egypt. After Moses and the LORD go back and forth about some of the logistical details, God makes a few concessions to his original plan in order to accommodate Moses. In the future those concessions will cause serious problems for the priesthood, but at the time described in this part of the book of Exodus, Moses and God agree to a version of the LORD’s plan that Moses is willing to do. Moses sets out, but it appears from the text that he immediately runs into a problem. God is angry and threatening to kill Moses. Turning to God’s Word author Matthew Phelps discusses why the LORD appears to be so upset and how the actions of Moses’ wife Zipporah turn things around. Matthew also considers how Moses’ actions now compare with those of Abraham. The book of Exodus records Moses’ conversation with God, but the book of Genesis, which includes many details about Abraham’s relationship with God, doesn’t include everything we’d now like to know about how the LORD introduces himself to Abraham.


The Scripture ranges for the videos that accompany this Catholic Bible study from Turning to God’s Word match the Scripture ranges for the sets of questions in You Shall Have No Other Gods: The Book of Exodus. You can follow along as Turning to God’s Word author Matthew Phelps discusses Lesson 4, “God Sends Aaron to Help Moses,” on pages 20–24 in the study book.

what’s the significance of these signs?
In the book of Exodus 4:1–9, God provides Moses with three signs. “They” in the book of Exodus 4:1 apparently refers to the elders of Israel, whom Moses and God have been most recently discussing in the third chapter of the book of Exodus. The signs that the LORD enables Moses to perform include changing a staff into a serpent, making himself leprous, and turning a small amount of water from the Nile River into blood. The relevance of these signs seems to be having the ability to reverse them.

Changing a staff into a serpent recalls what happened during Adam and Eve’s fall in the Garden of Eden, which is recorded in the third chapter in the book of Genesis. Being able to turn a serpent into a staff shows that Moses, acting on behalf of God, can neutralize the power of temptation. Moses being able to make his leprosy disappear demonstrates that God can make unclean things clean.

Perhaps the most significant sign is God’s ability to turn water to blood and then back into fresh water, indicating God’s power over life and death. As much as water symbolizes life, it’s something that allows a living thing to live and doesn’t represent life itself. Blood, however, was seen by the ancients as representing life itself. This is apparent in the book of Genesis 9:1–4, when the LORD tells Noah that he and his descendants now may eat the flesh of animals but may not consume blood—because: “Only you shall not eat flesh with its life, that is, its blood.” Learn more about the aftermath of the Flood in Lesson 6 The Great Flood & God’s Covenant with Noah in the Turning to God’s Word Catholic Bible study In the Beginning: The Book of Genesis.

who benefits most from the signs?
Although this won’t become immediately apparent, it’s Moses who stands to gain the most when God gives him the power to perform these three signs. For starters, the only sign that Moses actually performs exactly as God showed him is the first one, and he performs it in front of Pharaoh and not in front of the Israelites. (The book of Exodus 4:30 records that Moses’ brother Aaron apparently does perform all three signs in front of the Israelites.) Moses never does perform the sign involving leprosy, and when God decides it’s time to turn water to blood, the LORD doesn’t restrict this sign to a small amount of water from the Nile poured out on the ground. It seems that Moses’ reluctance to quickly agree to do as God has asked makes it necessary for God to demonstrate divine power in order for Moses to be comfortable with the idea of returning to Egypt and speaking to Pharaoh.

when does the sign involving leprosy recur?
The book of Numbers 12:1–16 records an instance in which Moses’ sister Miriam is struck with leprosy, recalling the second sign that God provides Moses in the book of Exodus 4:6–7 as a demonstration that the LORD would stand by him.

?  What precipitated Miriam’s leprosy?
?  What part did Aaron play in this event?
?  What does God tell Miriam and Aaron prior to striking Miriam with leprosy?
?  How long is Miriam required to stay apart from the rest of the Israelites?
?  What else in Scripture so far has happened in a similar amount of time?
?  What does this suggest might be happening now?

is Moses really demonstrating humility?
In the book of Exodus 4:10, Moses persists in making excuses for why he shouldn’t be the one sent to Pharaoh to free the Israelites from bondage in Egypt. Although God promises to provide Moses with the ability to speak to Pharaoh and the Egyptians, Moses still resists. The book of Exodus 4:14 records that the LORD’s anger was kindled against Moses. It seems highly unlikely that humility or even incompetence would cause God’s anger. If the LORD has called Moses, then Moses has no case to make for being unable to do what God asks of him. What this passage seems to show is that although we’re called to be humble, some of us also are called to do great things—and the two aren’t contradictory.

Moses is in the early stages of his relationship with God
It’s noteworthy that Moses isn’t yet the spiritually mature figure presented later in Scripture. He’s only just been introduced to God. In the early chapters of the book of Exodus, Moses appears as a person who doesn’t know the LORD. Moses quickly changes into someone whose weaknesses become strengths. (These weaknesses include acting rashly without judgment, not speaking well in public, hesitating, not practicing his own faith, etc.) God chose someone bad at all the things that Moses was going to be asked to do in order for the LORD’s divine power to be evident.

Aaron becomes a mouth for Moses & Moses becomes as God to Aaron
It’s worth noting that this idea wasn’t part of God’s original plan, and it leads to all manner of problems. Aaron isn’t Moses, and the consequences of this will continue to become apparent. It probably is fair to consider that things might have gone better without Aaron acting as an intermediary. This section of the book of Exodus ultimately appears to be a commentary about why God later will come to his people himself rather than trusting others to speak for him.

circumcision—you could look it up in our archives
The fourth chapter in the book of Exodus contains an unusual account of Moses’ wife circumcising their son. To learn more about circumcision as a sign of the Old Covenant and how it figures into the New Covenant understanding of the early Church, read Lost in Translation, an online column in which Turning to God’s Word author Matthew Phelps helps readers connect with ideas expressed in the original languages of the Scriptures. New Lost in Translation entries are posted on Mondays, and past entries are archived on our website. Contact us if you’d like to receive Lost in Translation by email every week.

a confusing passage
The book of Exodus 4:24–26 describes what at first reading appears to be a strange account of the LORD seeking to kill Moses after Moses has agreed to speak to Pharaoh and is on his way to Egypt with his wife and sons. The key to understanding what’s going on in this section can be found in the book of Exodus 4:21–23: “And the LORD said to Moses, ‘When you go back to Egypt, see that you do before Pharaoh all the miracles which I have put in your power; but I will harden his heart, so that he will not let the people go. And you shall say to Pharaoh, “Thus says the LORD, Israel is my first-born son, and I say to you, ‘Let my son go that he may serve me’; if you refuse to let him go, behold, I will slay your first-born son.”‘” Although Moses has agreed to act in accord with God’s wishes concerning the Israelites in Egypt, he apparently isn’t all-in with serving the LORD. If Moses were, he wouldn’t have neglected to circumcise his own first-born son. Moses has held back his child, and this is unacceptable behavior if Moses is to act for God. The opposite reaction can be seen in the twenty-second chapter in the book of Genesis, which describes Abraham’s unhesitating response when asked to sacrifice his son Isaac. You can learn more in Lesson 13  God Tests Abraham in the Turning to God’s Word Catholic Bible study In the Beginning: The Book of Genesis.

oops—two corrections in the study book
Both corrections occur in this lesson in You Shall Have No Other Gods: The Book of Exodus—one in the biblical text and one in Question 10.

In the biblical text on page 21 in You Shall Have No Other Gods: The Book of Exodus, the citation to the book of Exodus 4:18 has been corrected to read: “Moses went back to Jethro his father-in-law and said to him, ‘Let me go back, I beg, to my kinsmen in Egypt and see whether they are still alive.’ And Jethro said to Moses, ‘Go in peace.’”

Question 10—Read the book of Exodus 4:27–31. What moves Aaron to go into the wilderness to meet Moses? What in the biblical text suggests that Aaron does not share his brother’s hesitation to go to Egypt and do as the LORD has asked? With whom do Moses and Aaron first meet when they arrive in Egypt? How does Aaron know what words to speak? Who performs the signs that the LORD told Moses could be used to convince the people that Moses and Aaron were acting on God’s instructions? What does this suggest about the rod that Moses carried to Egypt from Midian? How do the elders of the sons of Israel react when they see the signs?

the best Catholic commentary about Scripture
To find out more about how Church teaching is supported by Scripture passages in You Shall Have No Other Gods: The Book of Exodus, check out the Index of Citations in the Catechism of the Catholic Church. Links to the primary Scripture passages in the lesson (Revised Standard Version Catholic Edition [RSVCE*]) and relevant paragraphs in the Catechism are provided here. Not every passage in the biblical text for this Catholic study is referenced in a Catechism paragraph, however.

the book of Exodus 4:22—paragraphs 238, 441

ways our glossary might prove helpful
In addition to providing extra information about geographical locations, our glossary also points out when a person or place is mentioned in the biblical text under more than one name or more than one spelling. If you can remember a name but aren’t sure in which lesson it shows up, you can find it in the glossary, which lists every proper noun that appears in the biblical text for every lesson in You Shall Have No Other Gods: The Book of Exodus.

to learn more, read more Scripture
If you’re having difficulty with a particular passage of Scripture, it can be helpful to read the relevant cross references—but looking these up can take time. To make that easier, we’ve compiled the cross references from the Revised Standard Version Second Catholic Edition (RSV2CE)—the translation that we reprint in our study books. That list can be found at the top of every online study page accompanying this study, and it includes links to each of the cross references in the primary biblical text for You Shall Have No Other Gods: The Book of Exodus.

don’t forget about our indexes & extra online material
If you’re trying to locate information about a specific Scripture passage, you can look it up in the index at the back of the study book or sample lesson. If you want to find a particular commentary, you can look up its title in the topics index. To learn more about another book of the Bible for which there’s a Turning to God’s Word study, visit the online study directories to read the commentaries and watch any accompanying videos. Finally, if you have a question or would like to make a comment about any of our studies, you can use one of the “ask us your question” or “what do you think” buttons to email our authors.

ex libris—Church documents & books about religious topics
Link to magisterial documents referred to in our Bible studies at ex libris—magisterial documents. This listing includes significant recent encyclicals as well as a number of historical Church documents. Recommended books related to Scripture study can be found at ex libris—main bookshelf.

wondering how to pronounce some of these words?
The following link is to a reading from the New International Version (NIV) Bible. To listen, open the link and click on the audio icon above the printed text. Although not taken from the translations used in our study materials, the NIV reading provides an audio guide to pronunciation of words in this lesson’s primary biblical text. A close online version of the translation of the Bible used in Catholic liturgy in the United States as well as an audio guide for daily Mass readings for the current month can be found on the website of the United States Conference of Catholic Bishops (USCCB).

the book of Exodus 4:1–31 (NIV)

round black doveclose with Bible-based prayer related to this lesson
Many of our Catholic study groups like to conclude their discussions with a prayer based on the scriptural focus of their lesson, and some participants include Scripture-specific prayer in their individual study. If you’re uncomfortable composing your own Bible-based prayers, you can follow our four easy steps. If you prefer, you can use the following short prayer based on this lesson’s text from the book of Exodus.

O God, you have great patience with us
when we hesitate to respond to your call
and instead offer excuses for not doing what you ask.
Help us to accept your assistance,
and give us the courage to trust you
with every aspect of our lives.
We ask this in the name of your Son, Jesus Christ,
who accepted your will in all things. Amen.

Lesson 5 Pharaoh Does Not Know the LORD, the book of Exodus 5:1–23
Lesson 3 God Reveals His Name: ‘I AM WHO I AM’, the book of Exodus 3:1–22

you also may like our study of Saul, David & Solomon
The United Kingdom of Israel: Saul, David & Solomon Foreshadow Christ the King, a 28-lesson Catholic Bible study with an imprimatur, provides an in-depth look at the First and Second Books of Samuel to learn how the lives of the monarchs Saul, David, and Solomon point ahead to the kingdom of heaven. The unified reign of King David is seen as a foreshadowing or type of the unity that is one of the four marks of the Church—the kingdom of God—established by Jesus Christ. Click on the book’s cover to view a sample lesson.

start a Turning to God’s Word Bible study
Thank you for your interest in You Shall Have No Other Gods: The Book of Exodus. Information about beginning a Turning to God’s Word Bible study can be found at start a Bible study. Tami, Matthew, and I are available to answer your questions and to offer support. You may use this email to contact us directly if you’re interested in starting a Turning to God study or in having your study schedule listed with other TtGW study groups on our website. —Jennifer

*There are seven deuterocanonical books in the Old Testament—the Books of Tobit, Judith, Wisdom, Sirach, Baruch, and First and Second Maccabees, as well as some passages in the Books of Esther and Daniel. Protestants usually refer to these works as “apocryphal,” a word that means “outside the (Protestant) canon” because they’re excluded from most Protestant Bibles. The word “deuterocanonical” means “second canon”; Catholics use that word to refer to any section of the Catholic Old Testament for which there are no extant, or existing, Hebrew manuscripts. All of the deuterocanonical books appear in the Septuagint, the earliest remaining versions of which date to the 1st century B.C. This Greek translation of the Old Testament was in common use by Jews at the time of Jesus. Learn more by reading How Do Catholic & Protestant Bibles Differ?

Turning to God’s Word printed Bible studies use the 2006 Revised Standard Version Second Catholic Edition (RSV2CE) translation for all Scripture references except those to the Psalms, which are taken from The Abbey Psalms and Canticles, prepared by the Benedictine monks of Conception Abbey and published in 2020 by the United States Conference of Catholic Bishops (USCCB). All Scripture links for the online study pages for You Shall Have No Other Gods: The Book of Exodus are to the 1966 Revised Standard Version Catholic Edition (RSVCE) translation. The New International Version (NIV) audio recordings follow the same chapter and verse numbering as the RSV Catholic translations, but the NIV translation doesn’t include the deuterocanonical books and passages.

The 1966 RSVCE uses archaic pronouns and verb forms such as “thee,” “thou,” “didst” in the Psalms and in direct quotations attributed to God. The 2006 RSV2CE replaces those with more accessible English. The few significant translation changes in the RSV2CE include rendering almah as “virgin” in the Book of Isaiah 7:14 and restoring the term “begotten” in the Gospel According to John 3:16.

Numbering varies for some passages in this Bible study. Turning to God’s Word studies (print and digital) follow the numbering in the Revised Standard Version Catholic translations (RSV2CE and RSVCE). Discrepancies in the New American Bible Revised Edition (NABRE) are noted in the Index of Scripture Citations in the study book and the online sample.

You can learn more about the Psalms by viewing a sample lesson from the Turning to God’s Word Catholic Bible study Sing a New Psalm: Communicating with God Through the Prayers of the Church—Volume I: Lauds & Vespers. The second part of that study, Sing a New Psalm: Communicating with God Through the Prayers of the Church—Volume II: Vigils, Day Prayer & Compline, is scheduled for publication in 2025. Some verse numbers may vary in different translations of the Psalms.