211 And the Lord visited Sarah as He had said, and the Lord did for Sarah as He had spoken. 2 For Sarah conceived and bore Abraham a son in his old age, at the set time of which God had spoken to him. 3 And Abraham called the name of his son who was born to him--whom Sarah bore to him--Isaac. 4 Then Abraham circumcised his son Isaac when he was eight days old, as God had commanded him. 5 Now Abraham was one hundred years old when his son Isaac was born to him. 6 And Sarah said, "God has made me laugh, and all who hear will laugh with me." 7 She also said, "Who would have said to Abraham that Sarah would nurse children? For I have borne him a son in his old age."
8 So the child grew and was weaned. And Abraham made a great feast on the same day that Isaac was weaned.
9 And Sarah saw the son of Hagar the Egyptian, whom she had borne to Abraham, scoffing. 10 Therefore she said to Abraham, "Cast out this bondwoman and her son; for the son of this bondwoman shall not be heir with my son, namely with Isaac." 11 And the matter was very displeasing in Abraham's sight because of his son. 12 But God said to Abraham, "Do not let it be displeasing in your sight because of the lad or because of your bondwoman. Whatever Sarah has said to you, listen to her voice; for in Isaac your seed shall be called. 13 Yet I will also make a nation of the son of the bondwoman, because he is your seed."
Matthew Henry's Commentary on Genesis 21:1-13
Commentary on Genesis 21:1-8
(Read Genesis 21:1-8)
Few under the Old Testament were brought into the world with such expectations as Isaac. He was in this a type of Christ, that Seed which the holy God so long promised, and holy men so long expected. He was born according to the promise, at the set time of which God had spoken. God's promised mercies will certainly come at the time which He sets, and that is the best time. Isaac means "laughter," and there was good reason for the name, Psalm 22:9,10; Hosea 11:1,2.
Commentary on Genesis 21:9-13
(Read Genesis 21:9-13)
Let us not overlook the manner in which this family matter instructs us not to rest in outward privileges, or in our own doings. And let us seek the blessings of the new covenant by faith in its Divine Surety. Ishmael's conduct was persecution, being done in profane contempt of the covenant and promise, and with malice against Isaac. God takes notice of what children say and do in their play; and will reckon with them, if they say or do amiss, though their parents do not. Mocking is a great sin, and very provoking to God. And the children of promise must expect to be mocked. Abraham was grieved that Ishmael should misbehave, and Sarah demand so severe a punishment. But God showed him that Isaac must be the father of the promised Seed; therefore, send Ishmael away, lest he corrupt the manners, or try to take the rights of Isaac. The covenant seed of Abraham must be a people by themselves, not mingled with those who were out of covenant: Sarah little thought of this; but God turned aright what she said.