Sarah.

Genesis 17:21
But I will establish My covenant with Isaac, whom Sarah will bear to you at this time next year."

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. . . .

Genesis 21:2, 3, 6
So Sarah conceived and bore a son to Abraham in his old age, at the very time God had promised him. . . .

2 Kings 4:16, 17
And Elisha declared, "At this time next year, you will hold a son in your arms." "No, my lord, " she said. "Do not lie to your maidservant, O man of God." . . .

Luke 1:13-20
But the angel said to him, "Do not be afraid, Zechariah, because your prayer has been heard. Your wife Elizabeth will bear you a son, and you shall give him the name John. . . .

Romans 9:6-9
It is not as though God's word has failed. For not all who are descended from Israel are Israel. . . .

Galatians 4:28-31
Now you, brothers, like Isaac, are children of the promise. . . .

Isaac.

Genesis 17:17
Abraham fell facedown. Then he laughed and said to himself, "Can a child be born to a man who is a hundred years old? Can Sarah give birth at the age of ninety?"