What does the Bible say about God's purpose of grace?

In Romans 9, the Apostle Paul articulates the doctrine of God's sovereignty in salvation, clearly stating that God's purpose of election stands apart from human merit. He uses the examples of Isaac and Jacob to illustrate that being a physical descendant of Abraham does not guarantee being a child of God. Instead, it is those chosen by God — the children of promise — who are considered His true heirs. This demonstrates that God's grace is not bestowed based on human effort or lineage, but solely based on His sovereign will and purpose.