Abraham trusted God to provide for him. Listen to how Abraham negotiated.
[Abraham]’s and Lot’s possessions were so great that they could not dwell together. So [Abraham] said to Lot: “Let there be no strife between you and me, Please separate from me. If you prefer the left, I will go to the right; if you prefer the right, I will go to the left.” Gen 13:7-9
[Abraham] stayed in the land of Canaan, while Lot settled … near Sodom. Gen 13:12
As great as Abraham’s faith and fidelity were, and as old as he was, he grew even more; through prayer.
… beginning with our father Abraham … prayer is revealed in the Old Testament. # 2569
Prayer unfolds throughout the whole history of salvation as a reciprocal call between God and [human beings]. # 2591
At first Abraham prayed by doing things. He built altars. As he grew in spirituality, he also prayed in words. # 2570
see also Gen 12:7-8 Gen 13:4-8
… one aspect of … prayer [is] the test of faith in the fidelity of God. #2570 see also # 2613
When our prayers are not answered yet, then we have an opportunity to grow in faith.
Did you ever pray, asking for something, and God was slow to answer?
Abraham waited twenty-five years for God to fulfill his prayers.
And Abraham let God know that he wanted descendents.
… this word of the LORD came to [Abraham] in a vision: “Fear not, [Abraham]! … I will make your reward very great.” But [Abraham] said, “O Lord GOD, what good will your gifts be, if I keep on being childless …?” Gen 15:1-2
[God] took [Abraham] outside and said: “Look up at the sky and count the stars, if you can. Just so,” [God] added, “shall your descendants be.” [Abraham] put his faith in the LORD, who credited it to him as an act of righteousness. Gen 15:5-6
Not his obedience, but Abraham’s faith in God was credited to Abraham as an act of righteousness.
Abraham put his faith in God. But Sarah thought she would help things along.
[Abraham]’s wife [Sarah] had borne him no children. Gen 16:1
… after [Abraham] had lived ten years in the land of Canaan,
(ten years after the promise of descendants)
his wife [Sarah] took her maid, Hagar the Egyptian, and gave [Hagar] to her husband [Abraham] to be his concubine. Gen 16:3
This was acceptable in the culture of the time.
Hagar bore [Abraham] a son, and [Abraham] named the son whom Hagar bore him Ishmael. Gen 16:15
[Abraham] was eighty-six years old when Hagar bore him Ishmael. Gen 16:16
But the birth of Ishmael was not the fulfillment of God’s promise to Abraham.
God needed to do something so dramatic and so impossible that Abraham’s descendents would believe that God does exist. The next step in teaching them faith needed to be clearly, miraculously, an act of God.