Is Abraham A Disgrace?

Leviticus 20:17 tells us that a man is not to marry his sister. We know, however, that Abraham and his wife Sarah were brother and sister. God blessed this marriage and even promised Abraham that He would make a great nation out of Abraham through Sarah. Obviously Abraham was not aware of this law since God didn't decree it until much later in history, specifically in the time after the Israelites were freed from Egypt. But why would God bless Abraham and Sarah's union so bountifully only to later decide that it was an offense worthy of excommunication?

Created almost 2 years ago