What does Genesis 17:15 mean?
In verse 5 of this chapter, God signaled a new stage in His relationship with Abram by changing his name to Abraham. This name is very similar to the Hebrew phrase meaning "father of a multitude," emphasizing that Abraham will be the father of nations and that kings would come from him.Now God tells Abraham that his wife Sarai's name is to be changed to Sarah. Both names apparently mean princess, though in the following verse God will call her the "mother of nations." While this seems like a slight change, it marks a significant new season in God's work in and through Sarah as well. This change will be especially amazing to Abraham, who will laugh out loud at the suggestion of Sarah giving birth (Genesis 17:17).
Later, during a significant encounter, God would change the name of Abraham and Sarah's grandson through Isaac. He will be renamed from Jacob to Israel (Genesis 32:28).