Galatians 4:28-31
Now you, brothers, like Isaac, are children of promise. / At that time, however, the son born by the flesh persecuted the son born by the Spirit. It is the same now. / But what does the Scripture say? “Expel the slave woman and her son, for the slave woman’s son will never share in the inheritance with the free woman’s son.” ...

Hebrews 11:11-12
By faith Sarah, even though she was barren and beyond the proper age, was enabled to conceive a child, because she considered Him faithful who had promised. / And so from one man, and he as good as dead, came descendants as numerous as the stars in the sky and as countless as the sand on the seashore.

Romans 9:7-9
Nor because they are Abraham’s descendants are they all his children. On the contrary, “Through Isaac your offspring will be reckoned.” / So it is not the children of the flesh who are God’s children, but it is the children of the promise who are regarded as offspring. / For this is what the promise stated: “At the appointed time I will return, and Sarah will have a son.”

Galatians 4:22-23
For it is written that Abraham had two sons, one by the slave woman and the other by the free woman. / His son by the slave woman was born according to the flesh, but his son by the free woman was born through the promise.

Genesis 17:19
But God replied, “Your wife Sarah will indeed bear you a son, and you are to name him Isaac. I will establish My covenant with him as an everlasting covenant for his descendants after him.

Genesis 18:10-14
Then the LORD said, “I will surely return to you at this time next year, and your wife Sarah will have a son!” Now Sarah was behind him, listening at the entrance to the tent. / And Abraham and Sarah were already old and well along in years; Sarah had passed the age of childbearing. / So she laughed to herself, saying, “After I am worn out and my master is old, will I now have this pleasure?” ...

Genesis 15:4-5
Then the word of the LORD came to Abram, saying, “This one will not be your heir, but one who comes from your own body will be your heir.” / And the LORD took him outside and said, “Now look to the heavens and count the stars, if you are able.” Then He told him, “So shall your offspring be.”

Genesis 22:2
“Take your son,” God said, “your only son Isaac, whom you love, and go to the land of Moriah. Offer him there as a burnt offering on one of the mountains, which I will show you.”

Genesis 25:1-2
Now Abraham had taken another wife, named Keturah, / and she bore him Zimran, Jokshan, Medan, Midian, Ishbak, and Shuah.

Genesis 30:1-2
When Rachel saw that she was not bearing any children for Jacob, she envied her sister. “Give me children, or I will die!” she said to Jacob. / Jacob became angry with Rachel and said, “Am I in the place of God, who has withheld children from you?”

Genesis 16:15-16
And Hagar bore Abram a son, and Abram gave the name Ishmael to the son she had borne. / Abram was eighty-six years old when Hagar bore Ishmael to him.

Genesis 24:36
My master’s wife Sarah has borne him a son in her old age, and my master has given him everything he owns.

Genesis 26:3-5
Stay in this land as a foreigner, and I will be with you and bless you. For I will give all these lands to you and your offspring, and I will confirm the oath that I swore to your father Abraham. / I will make your descendants as numerous as the stars in the sky, and I will give them all these lands, and through your offspring all nations of the earth will be blessed, / because Abraham listened to My voice and kept My charge, My commandments, My statutes, and My laws.”

Genesis 28:14
Your descendants will be like the dust of the earth, and you will spread out to the west and east and north and south. All the families of the earth will be blessed through you and your offspring.

Genesis 35:12
The land that I gave to Abraham and Isaac I will give to you, and I will give this land to your descendants after you.”