God promised to bless all the families of the Earth through Abraham, but when he finally had a son, his son Isaac and his wife could not have children. However, Isaac did something about it,

This is the genealogy of Isaac, Abraham’s son. Abraham begot Isaac. Isaac was forty years old when he took Rebekah as wife, the daughter of Bethuel the Syrian of Padan Aram, the sister of Laban the Syrian. Now Isaac pleaded with the LORD for his wife, because she was barren; and the LORD granted his plea, and Rebekah his wife conceived (Genesis 25.19–21).

The Lord had a plan that would be fulfilled through Isaac. Therefore, Isaac’s request harmonized with the will of the Lord, and He gave what Isaac wanted.

When you pray to God, be sure that you are praying with His will in mind, that you want the request filled, if it fits in with God’s will.