Abraham Obeyed on That Very Day: Genesis 17 and the Exodus Night

The Hebrew verb behind Abraham's laugh in Genesis 17:17 runs on through the next four chapters of Genesis. It turns up each time someone meets a promise from God that sounds absurd, and then, at a birth, it changes sides.

Where does Abraham's laugh go after Genesis 17?

The verb is tsachaq (H6711), "Then he laughed" (Genesis 17:17), and Isaac's name, Yitschaq (H3327), is built from it.

Follow it out of the chapter and it keeps turning up at the promise's edges. Sarah laughs to herself at the tent door when she overhears the same promise (Genesis 18:12). The root is there when Lot's sons-in-law think he is joking about the judgment coming on Sodom (Genesis 19:14), and again when Ishmael is "mocking her son" at Isaac's weaning feast (Genesis 21:9). Each time, the laugh is how someone meets a word from God that sounds absurd. Then at the birth the same root turns over. Sarah says, "God has made me laugh, and everyone who hears of this will laugh with me" (Genesis 21:6). The boy's name holds the whole story from the dust in chapter 17 to the cradle in chapter 21. In Genesis a name is a record, and this one recorded that God heard a laugh and answered it with a son.

Some of the oldest Jewish readers heard joy in Abraham's laugh. The Aramaic Targum Onkelos, the translation read aloud in synagogues, renders verse 17 and Abraham rejoiced. Set that beside what Jesus said to the crowd in the temple: "Your father Abraham rejoiced that he would see My day. He saw it and was glad" (John 8:56). Doubt or joy, God kept Abraham's laugh in the boy's name for every generation to say, and Jesus says the joy in it was fixed on Him.

What does Ishmael's name have to do with God's answer?

Verse 20 opens with the boy's name and answers it in the next word: ul'Yishmael shema'tikha, "As for Ishmael, I have heard you" (Genesis 17:20). Yishmael (H3458) means God hears, built on shama (H8085), to hear. The angel first gave Hagar that name in the wilderness, "for the LORD has heard your cry of affliction" (Genesis 16:11). Now the father pleads for the same boy, and God answers with the verb already sitting inside the boy's name. So the two boys named in consecutive sentences both carry the sound of this conversation: one his father's laugh, the other the verb God used to answer.

Abraham's plea also made sense by the law of his world. Under the Laws of Hammurabi (section 170), if a man's slave woman bore him sons and he acknowledged them as his children while he lived, they shared the estate with his wife's sons after his death. By the customs Abraham lived among, a thirteen-year-old firstborn by Sarai's own maid was already an heir. "O that Ishmael might live under Your blessing!" (Genesis 17:18) asks God to confirm what the culture had settled. God blesses Ishmael without stinting, and the twelve rulers promised here, each a nasi (H5387), a lifted-up one, appear by name eight chapters later as "twelve princes of their tribes" (Genesis 25:16).

Why did Abraham obey on that very day?

Verse 23 says Abraham obeyed be'etsem hayyom hazzeh. The middle word is etsem (H6106), the ordinary Hebrew for bone, and here it means the day's own substance: in the bone of this day. The phrase is rare. Genesis uses it for the flood: "On that very day Noah entered the ark" (Genesis 7:13). The Day of Atonement is fixed with it in Leviticus 23:28. And it is the phrase for the exodus: "on that very day the LORD brought the Israelites out of the land of Egypt by their divisions" (Exodus 12:51).

The people who first heard Genesis read were a nation just out of Egypt, and that very day was the phrase for the night their own story began. They also knew that the mark and the feast belonged together: at the Passover, "no uncircumcised man may eat of it" (Exodus 12:48). Their children kept the same order at Gilgal: Joshua circumcised the generation born in the wilderness before they kept their first Passover in Canaan (Joshua 5:10). So when Israel heard the verse about Abraham open with "On that very day" (Genesis 17:23), they heard the words of their own rescue attached to their father's obedience. The mark on their bodies began as a same-day answer to a God who had only just finished speaking, and each of them carried it into the Passover meal.

How does the child of promise point to Jesus?

In the next chapter God asks Abraham, "Is anything too difficult for the LORD?" (Genesis 18:14). The Greek Old Testament, the Bible of the early church, renders the question with rhema (G4487), a spoken word: is any word impossible with God? Gabriel takes that question and turns it into a statement for Mary: "For no word from God will ever fail" (Luke 1:37). The question God put to Abraham about Sarah's laugh comes back as the promise to the mother of Jesus.

He speaks a promise with a name and a date on it, He hears the laugh and the plea that come back, and He writes His hearing into two boys' names so Israel could never read the story without meeting it. Knowing Him starts there. Tell Him what you honestly think of what He said, then act on it in the bone of the day He said it.