What does the Bible teach about God's covenant with Isaac?

In Genesis 17, God establishes His everlasting covenant specifically with Isaac, signifying that Isaac would be the heir through whom God's promises would be fulfilled. This covenant is a pivotal moment that points to the future work of Jesus Christ, as Isaac represents the lineage through which salvation would come. While Abraham had a son, Ishmael, born out of his and Sarah's attempt to fulfill God's promise through their own means, it is Isaac through whom the covenant blessings would be manifested. This not only illustrates God's faithfulness and sovereignty in choosing and preserving a remnant but also reminds believers that salvation is rooted in God's grace and is not based on human effort.