Let's dive into the Holy Scripture and explore God's reasons.
When Abram was 99 years old, the Lord appeared to Abram and said to him, “I am El Shaddai. Walk with me and be trustworthy. I will make a covenant between us and I will give you many, many descendants.” Abram fell on his face, and God said to him, “But me, my covenant is with you; you will be the ancestor of many nations. And because I have made you the ancestor of many nations, your name will no longer be Abram but Abraham.
I will make you very fertile. I will produce nations from you, and kings will come from you. I will set up my covenant with you and your descendants after you in every generation as an enduring covenant. I will be your God and your descendants’ God after you. I will give you and your descendants the land in which you are immigrants, the whole land of Canaan, as an enduring possession. And I will be their God.”
Isaac:
Isaac was Abraham's son that he bore from his wife Sarah. God had promised him a son through this line, but he'd gotten impatient when years passed and nothing happened. Worried he would have no offspring by the time he passed, he slept with Hagar, a slave in his household. From that union came Ishmael.
(The Israelites and descendants of Ishmael have been at war ever since.)
Isaac son born to Abraham and Sarah in their old age. Was one of Israel’s great founding fathers.
When famine struck, Isaac moved his family to Gerar. The Lord blessed him, and Isaac became a prosperous farmer and rancher, later moving to Beersheba.
(Genesis 26:23).
Isaac favored Esau, a burly hunter and outdoorsman, while Rebekah favored Jacob, the more sensitive, thoughtful of the two. That was an unwise move for a father to take. Isaac should have worked to love both boys equally.
Although Isaac was less prominent in the patriarchal narratives than his father Abraham and his son Jacob, his faithfulness to God was evident and remarkable. He never forgot how God saved him from death and provided a ram to be sacrificed in his place. He watched and learned from his father Abraham, one of the most faithful men of the Bible.
In an era when polygamy was accepted, Isaac took only one wife, Rebekah. He loved her deeply all his life.
God answers prayers. He heard Isaac's prayer for Rebekah and allowed her to conceive.
God ears our prayers too and gives us what is best for us.