You do not mention the title of the book, poem or play you are working on, so I will give you an overview of the story of Abraham and Isaac in the Bible. Abraham and his wife Sarah were very old - over 90 years old - and they had no children. God had promised to make Abraham the father of many nations. Yet into their 90s, they still did not have any children. Sarah decided to hurry things up, so she made Abraham sleep with her servant, Hagar. In those days, if a slave woman had a child, that child was considered to be the child of the master and his wife. Hagar had Ishmael. But God let Abraham know that this was not HIS plan. Ishmael was not the promised child. Finally, an angel appeared and told Sarah and Abraham that they would have a child. Sarah laughed! But, 9 months later, Isaac was born. He was the child of the promise. Abraham was a great man of faith to the Jews. God wanted to test his faith, so he told Abraham to make a sacrifice, as Jews were supposed to do back in those days, and the sacrifice was to be his son, Isaac. Abraham went up on a mountain with Isaac. Isaac, a young boy, asked his father, "Where is the lamb for the sacrifice?" Abraham, full of fear but a many of obedience, replied that "God would supply the lamb for the sacrifice." Abraham laid Isaac down on the altar of sacrifice. Just as Abraham was about to bring the the knife down to kill Isaac, God intervened and stopped Abraham. Isaac went on to grow up, marry and have children (Jacob and Esau), from whom he had grandchildren, great-grandchildren, etc. - as many as the stars in the sky, just as God had promised. In this way, Abraham was the father of the Jewish race.
How does this relate to your story? You will have to re-post your question and give us more information.