(a) A covenant is a mutual agreement between two parties, each pleading allegiance to its own responsibility or duty according to the terms of covenant. The two parties in the covenant could be equals or one could be superior to the other. The breach of the terms by any of the parties determines/terminates the covenant unless the other party forgoes its legal right and allows the covenant to subsist.

(b) One of the conditions stipulated in the covenant was God's promise that Sarah would bear Abraham a son in his old age (to be called Isaac). Although Abraham expressed a doubt (owing to his old age and the age of his "barren" wife), God assured him of his faithfulness. Then Abraham suggested that Ishmael might be the vehicle for God's fulfillment of the covenant. `No', said God. Sarah would bear a son with whom the covenant would be established with his descendants for ever. As for Ishmael, God would bless him with children, but Sarah's son, Isaac, would surely be born at that season the following year. Soon after this, she conceived and bore a son. Abraham called his name 'Isaac' and circumcised him on the eighth day. Abraham was 100 years old then. Sarah said that God had made laughter of her. Abraham celebrated the occasion with feast for his faithfulness to the covenant.