Romans 9

Paul makes the point that we are not God's children by physical birth; we are grafted into His family through God's mercy. Therefore, not all Jews will enter into God's promise, but some Gentiles will. God can extend His mercy to whomever He pleases and it is not for us to second guess Him in these matters.

Many people want to paint God as unfair because of the way they perceive He deals with us. The problem is that we can't apply our standards to the actions of God. He knows and understands infinitely more than we ever will about the world we live in, His plan of salvation, and each of us individually. We may not have all the answers to all of the questions, but one thing we must believe is that God is fair. For us to say that God is unfair is for us to second guess the omniscient Creator of the universe.