Genesis 20:17

20:17 Abraham prayed to God, and God healed Abimelech, as well as his wife and female slaves so that they were able to have children.

Genesis 25:21

25:21 Isaac prayed to 1  the Lord on behalf of his wife because she was childless. The Lord answered his prayer, and his wife Rebekah became pregnant.

1 tn The Hebrew verb עָתַר (’atar), translated “prayed [to]” here, appears in the story of God’s judgment on Egypt in which Moses asked the Lord to remove the plagues. The cognate word in Arabic means “to slaughter for sacrifice,” and the word is used in Zeph 3:10 to describe worshipers who bring offerings. Perhaps some ritual accompanied Isaac’s prayer here.