Read Romans 4:13-25
13 When God promised Abraham and his descendants that the world would belong to him, he did so, not because Abraham obeyed the Law, but because he believed and was accepted as righteous by God. 14For if what God promises is to be given to those who obey the Law, then faith means nothing and God’s promise is worthless. 15The Law brings down God’s anger; but where there is no law, there is no disobeying of the law. 16And so the promise was based on faith, in order that the promise should be guaranteed as God’s free gift to all of Abraham’s descendants—not just to those who obey the Law, but also to those who believe as Abraham did. For Abraham is the spiritual father of us all; 17as the scripture says, “I have made you father of many nations.” So the promise is good in the sight of God, in whom Abraham believed—the God who brings the dead to life and whose command brings into being what did not exist. 18Abraham believed and hoped, even when there was no reason for hoping, and so became “the father of many nations.” Just as the scripture says, “Your descendants will be as many as the stars.” 19He was then almost one hundred years old; but his faith did not weaken when he thought of his body, which was already practically dead, or of the fact that Sarah could not have children. 20His faith did not leave him, and he did not doubt God’s promise; his faith filled him with power, and he gave praise to God. 21He was absolutely sure that God would be able to do what he had promised. 22That is why Abraham, through faith, “was accepted as righteous by God”. 23The words “he was accepted as righteous” were not written for him alone. 24They were written also for us who are to be accepted as righteous, who believe in him who raised Jesus our Lord from death. 25Because of our sins he was handed over to die, and he was raised to life in order to put us right with God.
"Abraham believed and hoped even when there was nor reason for hoping." - Romans 4:18
Trusting and believing gave Abraham the power to carry on.
Give me the faith to trust in you O Lord.