The Son of Promise
All that Hear Will Laugh
Genesis 21: 1-10

Do not think, though, that everyone is going to be happy when God works in your life. Some may be jealous of your blessing and the favor that God shows you. Be thankful to the Lord through this, and ask Him to bless these people as well. Remember do unto others as you would have them do unto you. This is the true Christian walk.

Gen 21:1 And the LORD visited Sarah as he had said, and the LORD did unto Sarah as he had spoken.
Gen 21:2 For Sarah conceived, and bare Abraham a son in his old age, at the set time of which God had spoken to him.
Gen 21:3 And Abraham called the name of his son that was born unto him, whom Sarah bare to him, Isaac.
Gen 21:4 And Abraham circumcised his son Isaac being eight days old, as God had commanded him.
Gen 21:5 And Abraham was an hundred years old, when his son Isaac was born unto him.
Gen 21:6 And Sarah said, God hath made me to laugh, so that all that hear will laugh with me.
Gen 21:7 And she said, Who would have said unto Abraham, that Sarah should have given children suck? for I have born him a son in his old age.
God Protects Hagar and Ishmael
Gen 21:8 And the child grew, and was weaned: and Abraham made a great feast the same day that Isaac was weaned.
Gen 21:9 And Sarah saw the son of Hagar the Egyptian, which she had born unto Abraham, mocking.
Gen 21:10 Wherefore she said unto Abraham, Cast out this bondwoman and her son: for the son of this bondwoman shall not be heir with my son, even with Isaac.

Galatians 4:22-31
Genesis 17:17
Genesis 18:13
Psalms 22:9-10
Hosea 11:1-2

Union Gospel Press
Believers Bible Commentary
esword.com
Matthew Henry Concise Commentary
https://www.biblestudytools.com/commentaries/matthew-henry-complete/
http://www.bible-studys.org/index.html