Hi there! Have you ever heard of a special book called the Book of Genesis? It's a part of the Bible, which is a big book that tells stories about God and how the world was created.
One of the stories in the Book of Genesis talks about a man named Abraham. Abraham had a wife named Sarah who was very beautiful, but they didn't have any children. However, God promised Abraham that he would have many children and become a father to many nations.
But Sarah was getting older and still couldn't have children, so she decided to let Abraham have a child with her maid, Hagar. Hagar had a son named Ishmael, but this wasn't what God had planned for Abraham and Sarah.
Later on, God blessed Sarah with a baby boy named Isaac, who was the child that God had promised to Abraham. This was a miracle because Sarah was very old.
Now, here's where the wife-sister part comes in. When Abraham and Sarah traveled to a new place, Abraham was worried that the people there would want to take Sarah away from him because she was so beautiful. So he told everyone that Sarah was his sister, not his wife.
One time, a king named Abimelech saw Sarah and wanted to make her his wife. But God warned Abimelech in a dream that Sarah was actually Abraham's wife and he shouldn't touch her. Abimelech was scared and gave Sarah back to Abraham.
Abraham realized that pretending Sarah was his sister wasn't a good idea and he should have trusted that God would protect them. So in the end, Abraham and Sarah learned to have faith in God and trust that he would take care of them, even when things seemed scary.
So that's the wife-sister story in the Book of Genesis, and it teaches us to have faith and trust in God.