According to Genesis 17, "When Abram was 99 years old, the Lord appeared to Abram and said to him, “I am El Shaddai.[a] Walk with me and be trustworthy. 2 I will make a covenant between us and I will give you many, many descendants.”
Technically he made the covenant for eternity. God said as long as you believe in me I will bless you and your wife a child. Your children will flourish and become rulers of a great nation. So how long the covenant that they made lasted is lifelong. Abraham made the covenant with God for eternity.
