God is specific and intentional. Listen to today's Bible Minute.
In order for Jesus to be the Messiah according to God's plan, He had to be descended from Abraham. He had to be descended through Isaac, the son of promise. And in Luke 3:34 it says, "He was the son of Jacob, the son of Isaac, the son of Abraham."
So now we have Jesus, who is the seed of the woman, who is a descendant of Abraham, and then a descendant of Abraham through Isaac. But then he goes on and he says, "Not just through Isaac, but through one of Isaac's sons." It was through Jacob that Jesus would come.
So the prophecy then takes us from all the people on the face of the earth to just those who were descendants of Abraham, through Isaac through Jacob, the grandson of Abraham.
Jesus came from a specific family line--and there's a reason for that. Find out more from God's Word at backtothebible.org.