Genesis Chapter 21 Questions and Answers

In Genesis Chapter 21, we see the purpose, power, and faithfulness of God in His promise fulfilled.  We also see how Sarah relied again on her own power and didn't rest in God's promise.

About these Answers

Day One

1.   What are the three ways we can see in the first five verses that Isaac's birth is a result of divine intervention or the promise of God?

The Lord:

  • came to Sarah "as He had said" - verse 1
  • did for Sarah "as He had promised"  - verse 1
  • allowed Sarah to become pregnant and she bore a son to Abraham "at the appointed time God had told him" - verse 2

2.  What are two ways we see Abraham obey God in the first five verses?


  • named his son Isaac as the Lord had commanded him - Genesis 17:19
  • circumcised his son Isaac on the eighth day of his life as the Lord had commanded him - Genesis 17:10

Day Two

3.  How does a review of the following passages of Scripture help us understand Sarah's views over time regarding her ability to have children?

  • Genesis 11:30 - Sarah must have understood she was unable to conceive
  • Genesis 16:1-6 - Sarah states that the Lord had prevented her from conceiving
  • Genesis 18:9-15 - Sarah doubts that she could conceive but likely doesn't understand who's making the promise 
  • Genesis 21:6-7 - Sarah attributes her conception and the birth of her son Isaac to God
  • Hebrews 11:11 - Sarah believed God who had promised she would conceive was faithful to bring to pass the impossible

4.  According to the Guinness Book of World Records, at the time this Bible study's publication (February 2016), the oldest man to father a child did so at the age of 92 years and ten months; and the oldest woman to conceive naturally did so at the age of 59 years. 

Because the Guinness rules require record verification, it seems unlikely the Guinness judges will consider the ages of Abraham (100) and Sarah (90) to be world records despite the authority of the Word of God.

And despite the authority of the Word of God and His demonstrated faithfulness, both Abraham and Sarah laughed when they were told by God that Sarah would give birth to a son for Abraham. 

  • According to Genesis 17:17, Abraham laughed and said to himself "Can a child be born to a hundred-year-old man?  Can Sarah, a ninety-year-old woman, give birth?" 
  • According to Genesis 18:12, Sarah laughed and said to herself "Can I really have a baby when I'm old?"

Of course, God knew their thoughts.  He instructed Abraham to name the son Sarah would bear him Isaac (17:19), which in Hebrew means laughter.  What was the effect of naming Abraham's son "laughter"?

Sarah had been barren and unable to conceive children as early as twenty-five years prior to this (11:30).   Now at age 90, she's beyond the age of childbearing (18:11) and had produced no heir for the family (15:3; 16:1).

What God did in telling Abraham to name his son laughter is to bring honor to Himself.  Every time someone would learn of the name of Isaac, they would want to know why he was named laughter.  The only possible response is the story of God's miraculous power in granting a 90-year-old woman a child. 

This story magnifies that nothing is impossible with God and served to constantly remind Abraham, Sarah, and Isaac that God is all powerful and He is faithful to keep His promises.  Despite both Abraham and Sarah laughing at the prospect that such elderly people could have a child, God kept His promise and brought them both joy and Isaac - that is laughter - as Sarah proclaims in verse 6.

Not only would Sarah laugh, but verse 6 says that all who would hear of her miraculous motherhood would join her in the joy of her laughter - her Isaac.  This can only bring joy and glory to the Almighty God of Abraham, Sarah, and Isaac.

Day Three

5.  Before Abraham had any children, he worried that he was childless and complained to God that a slave born in his house would be his heir.  God responded that Abraham would have an heir and he would come from Abraham's own body (15:3-4). 

Then Sarah gave Abraham her slave Hagar to be his wife so Sarah and Abraham could build a family by Hagar (16:1-3).  After Hagar bore a son Ishmael to Abraham, God told Abraham that Sarah would have a son to which Abraham replies: "If only Ishmael were acceptable to you!" (17:18).  Obviously Abraham loved his son Ishmael born of a slave in his house.

So Sarah has Isaac and then complains to Abraham about Ishmael.  She asks that he and his mother be sent away so that the son of a slave will not be a co-heir with her son Isaac (21:10).  She does this once Isaac is weaned and therefore beyond the feebleness of the first years of infancy (hence the feast).  She also does this because she saw Ishmael mocking or laughing - presumably with Isaac as the target.

Verse 11 of Genesis chapter 21 tells us this was a very difficult thing for Abraham.  In what two ways does God reassure Abraham about Sarah's request and convince him to send Hagar and Ishmael away?

God told Abraham (verses 12 and 13):

  • Not to be concerned because his offspring would be traced through Isaac
  • That He would make a nation of the slave's son because he was Abraham's offspring

In other words, God told Abraham that they wouldn't just survive, they would thrive with His blessings. 

Before this assurance, God had promised Abraham previously that He would bless Ishmael, make him fruitful, multiply him greatly, that He would make him the father of 12 tribal leaders, and that He would make Ishmael into a great nation (17:20).  When Abraham sent Hagar and Ishmael away, he rested on God's promise to protect and prosper them.

6.  Review Galatians 4:21-31.  How does this New Testament passage help us understand how Christians today relate to this story of Isaac and Ishmael in Genesis chapter 21?

When Christians are born again, they are born again, by the Spirit of God; and like Isaac, by the promise of God.  And like Isaac, Christians are miraculously born (again).  

Then, they aren't further (as they were previously) under the law of sin.  That is, they don't remain enslaved to sin as they were born (like Ishmael).

Day Four

7.  Sarah asked Abraham to banish Hagar and her son because she didn't want Ishmael to be a co-heir with her son Isaac (21:10).  What was it that Isaac was to inherit as an heir to Abraham? 

Abraham was a very rich man because God promised He would make him extremely fruitful (17:6).  Abraham owned:

  • flocks and herds of donkeys and camels (12:16)
  • sheep and cattle (20:14)
  • male and female slaves (15:16; 20:14) - hundreds of which were trained to fight (14:14) 
  • silver and gold (13:2; 20:16)

More than all that and most importantly, God gave Abraham the Promised Land.  He promised Abraham that He was giving him and his descendants the Promised Land forever (15:14-15). 

God confirmed by His covenant that He was giving the land; however, God explained that Abraham was not to possess it at the time of the covenant (15:13-16).  God explained that the land would be possessed by Abraham's descendants (15:18-19).

Day Five

8.  What was the advantage to Abimelech to enter into a treaty with Abraham; or, why might Abimelech have sought a treaty with Abraham?

In verse 22 Abimelech, tells Abraham that "God is with you in everything you do".  Abimelech was visited by the God of Abraham and knew that if he had harmed Abraham by taking Sarah that he and his nation would be destroyed (20:3-7).  Also, he likely was informed about the miraculous birth of Isaac to Sarah, the 90-year-old wife of Abraham. 

It's likely that Abimelech and his household were again terrified regarding the God of Abraham.  Now they weren't dealing with a very old man who they likely thought would pass  away soon, they were dealing with a family - obviously born miraculously by no other means than by God's power.  

Abmilech must have thought that surely the God who caused such a miraculous birth would protect Abraham's blessed son.  It seems to reason that the God of Abraham would protect this growing family with the same degree of concern and watchfulness.  Therefore, it was to Abimelech's advantage to ensure peace with the God of Abraham through Abraham.  

Abraham was successful because God was making his name great (12:2).  Abimelech was successful because God had promised that those who blessed Abraham would be blessed (12:3) and he recognized the blessings of God on Abraham (21:22).  Therefore, the family of Abraham could live and enjoy peace because of the promised blessings of Almighty God in a foreign land.

We pray these Genesis Chapter 21 questions and answers have been a blessing to you.

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