Read: Genesis 16-18
Marked: Genesis 17:19, Then God said: “No, Sarah your wife shall bear you a son, and you shall call his name Isaac; I will establish My covenant with him for an everlasting covenant, [and] with his descendants after him.
God promises to make an everlasting covenant with Abraham (V2). Abraham is to become the father of many nations (V4). But Abraham was old and advanced in years, and so was his wife; well beyond the age of child bearing.
Further, God promises to keep the covenant with the descendants of Abraham (V 7). As a sign of the covenant, God commanded Abraham and his descendants, to be circumcised, literally a sign in the flesh. God confirms His plan by blessing Sarah with a child. She will become a mother of nations; kings of peoples shall be from her (V16).
Finally, God promises to fulfill the covenant through Isaac, born of Abraham and Sarah (V19). This promise of God, this covenant, is seen fulfilled in the genealogy of Jesus (Mathew 1:2) in which we see Abraham and Isaac and also in Luke 3:34.
But the genealogies in Matthew and Luke are different. Matthew traces the lineage of Jesus to Isaac through His adoptive earthly father, Joseph, while Luke traces His lineage to Isaac through His mother, Mary.
God is a covenant keeping God as we see through both Mary and Joseph. When God makes a plan we can be sure He’ll keep it.
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