Genesis 21:2  “…at the set time of which God had spoken…”
Several previous time references seemed to point to the end of a normal human gestation.  This one suggests that God gave them a more specific time frame.  At any rate, God fulfilled His promise just as He said.

3  “And Abraham called the name of his son who was born to him—whom Sarah bore to him—Isaac.”
God had told him the name in chapter seventeen.  Text is very specific about Isaac’s origins.  He was born to Sarah, not a surrogate.

6  “…God has made me laugh, and all who hear will laugh with me”
She’s laughing from joy now, not from disbelief as before.  Scripture tells us that children are a gift from God.  They were very important to those of that time.  A woman who could not have children did not feel complete.  The joy of finally having a child, and a male heir at that, was accented by the fact that she was past the normal child bearing age.  God certainly had a hand in what had happened.

8-9  “…Abraham made a great feast on the same day that Isaac was weaned…Sarah saw the son of Hagar…scoffing”
Commentaries suggest this feast at the weaning of the child was also the occasion of formally presenting him as the heir.  Ishmael would have understood this and realized the fact that, even though he was the firstborn of Abraham, he was not going to be Abraham’s heir.  Paul mentions this episode in Galatians.

11  “…the matter was very displeasing in Abraham’s sight…”
Abraham has always shown care and affection for his son Ishmael.  Even if Ishmael weren’t to be his heir, he still did not want to send him away.

12  “…in Isaac your seed shall be called”
The lineage of promise is through Isaac.  It’s not enough to be a descendant of Abraham.  The promise was fulfilled through Isaac and Jacob.

13  “…I will also make a nation of the son of the bondwoman, because he is your seed”
God is keeping His promise to Abraham’s son, even though Ishmael was outside the plan.  He is also fulfilling His promise to Hagar.

14  “…bread and a skin of water…sent her away…”
I’m wondering why such meager supplies.  Could not Abraham have given them more physical possessions and sent them somewhere specific, such as back toward the east where his family was?  Commentaries suggest Abraham probably did provide other material means, the water and bread just mentioned as they would be the supply for the journey.  Abraham was near the Gaza area of Israel at the time, the southern part of the country.  He probably gave Hagar enough supplies to reach Egypt where she would probably still have family and/or friends.  The statement that she wandered in the wilderness may mean she had gotten lost.  God was watching even though they got off track.  The situation looked hopeless to her, but He was keeping His promise.

22  “…Abimelech and Phichol…swear to me by God that you will not deal falsely with me…according to the kindness that I have done to you, you will do to me”
Abimelech still wants an alliance with Abraham.  Sad that he had to ask Abraham to swear that Abraham wouldn’t be dishonest with him.  Our witness before others is so important.

25-32  Contention over a well.  In the course of making an alliance, Abraham brings up a point of contention.  Abimelech explains his side of the issue, and they work it out.  Perhaps Abraham recognizes his previous error in Abimelech’s not-so-subtle mention of honest dealings.  Bringing all issues to the table would be showing good faith.

32-34  “…Abimelech rose with Phichol…they returned to the land of the Philistines…Abraham stayed in the land of the Philistines many days”
Confusing notions here geographically.  Contention over the well was with Abimelech’s servants so Abraham must have been in Philistine territory.  Then Abimelech leaves to return to his land, but Abraham stayed in the land.  Probably general labels for the area.  Abimelech was from Gerar.  Abraham has apparently left the city, but is still in what was considered Philistine territory.  Commentary suggests Beersheba was on the borders of Philistia.  Saying Abimelech returned to the land of the Philistines was probably a reference to Gerar.  All of the land was part of what God gave to Abraham and his descendants, yet they never drove out the Philistines.  Even today they have given the area of the Gaza strip to Arabs living there.  I don’t think God was too pleased with the action based on things that happened at that time.  God has given the land to the Israelis.  He expects it to stay that way.

I hope you enjoy reading and studying His word.  May it accomplish what He desires.  Please feel free to comment or post questions.  Thanks for reading!

Scripture taken from the New King James Version®. Copyright © 1982 by Thomas Nelson. Used by permission. All rights reserved.