The two convenants

The story of Isaac and Ishmael is an allegory of the covenant of the law and the covenant of grace with God. The law came first into the world through Moses to Israel, but Grace was the promise that would come through Jesus. Grace is the better covenant, the blessed covenant, and one that provides security and safety to the children of God. There is no blessing in the law because we cannot live up to it and even if we did we have only done our reasonable service. But with Grace comes the promises and blessings of Christ that we can be both sons and joint-heirs with Him unto Glory. That covenant made by God with Jesus, we are beneficiaries of through Him.