Genesis 21 – The Birth of Isaac

Genesis 21

In Genesis 21, God has fulfilled His promise to Abraham. Sarah has borne him a son, and Abraham has named him Isaac, as God told him in chapter 17. Isaac means “he laughs” (remember Sarah and Abraham laughing at the idea of people so old having a child in 17:17 and 18:12?). Whatever you sow, that also you reap, and Abraham’s earlier mistake with Hagar brings unhappiness. Sarah has weaned Isaac, and finds Ishmael laughing (the Hebrew suggests laughing as in mockery). She wants Hagar and the boy to leave, which displeases Abraham. But God tells him to do as she says, and he sends Hagar and Ishmael on their way with some food and water into the wilderness.

Beginning in verse 15, understanding has been a little difficult for me, but here is how I have sorted it out. In chapter 18, Abraham was 99 years old when Ishmael was circumcised at the age of thirteen. Isaac was born when he was 100 years old (21:5) So Ishmael was 14 then. The weaning of Isaac in verse 8 could have taken place at the age of two or even three years. So Ishmael would be 16 or possibly even 17 years old when they left.

After they leave, verse 15 says that when the water was gone, she put the boy under a bush. From the text that follows, she clearly expected him or both of them to die. The text does not say so, but it seems likely that Ishmael was either sick or weak from lack of water and food or both. God heard the voice of the boy – v 17- and her crying (Ishmael means “God hears”) and told her not to be afraid because He was going to make Ishmael a great nation – a promise He kept, of course. His Arab descendants are plentiful. When God opened her eyes there was a well of water.  The boy became an expert with the bow and took a wife from Egypt.

Abraham made a treaty with Abimilech after a disagreement over a well, that they would deal fairly with each other. God was still taking care of him. Abimilech and his army returned to the land they came from.  The place of the treaty was named Beersheba in verse 31.

(Side note: Here is an  interesting article about Beersheba.)

Read or listen to audio of ESV version of this selection from this link.


Please note: I did not design the reading plan that I am following in my blog.  All of my comments in this blog, however, are solely my responsibility.  When reading ANY commentary, you should ALWAYS refer first to the scripture, which is God’s unchanging and unfailing word. Reading schedules, as well as a link to the site where you can get the reading plan that I’m currently following for yourself can be found on the “Schedules” page of my website at  For questions and help, please see the “FAQ” and “Summaries” pages there.

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