When God makes a promise..He fully intends on keeping it.

"No distrust made him waver concerning the promise of God, but he grew strong in his faith as he gave glory to God, fully convicnced that God was able to do what he had promised." (Romans 4:20)

This passage talks about Abraham's faith in God's promise that he would be the father of many nations, as well as his offspring. Despite his physical limitations, Abraham had faith beyond what his mind could imagine.

We have to have faith in "Him who is able to do far more abundantly than allthat we ask or thinki according to the power at work WITHIN us, to him be glory..." (Ephesians 3:20)