Abrahamβs faith in God was strong. When God called him to forsake his family, friends and country, he obeyed and βwent forth, not knowing whither he went.β When God promised to multiply his seed as the stars of heaven, he believed it, though childless. When, in his old age, God promised that he would still have a son by ninety-year-old Sarah, he believed it even though he had waited so long, seemingly in vain. When God promised to give his seed the land in which he had sojourned, he believed it, though all reason argued against it. When God asked him to offer in sacrifice the son born so late in life, the son upon whom all the promises depended, he obeyed, concluding that it must be Godβs plan to raise him from the dead!
Such was Abrahamβs faith in God! Three times this is emphasized in Romans 4 alone: He was βnot weak in faithβ (Rom. 4:19); he βstaggered not at the promise of God through unbelief,β but was βstrong in faithβ (Rom. 4:20).
But it was not the strength of Abrahamβs faith that saved him; it was the fact that the object of his faith was God (See again Gen. 15:6). He had placed his faith in the right Person. His faith became βstrongβ only because he had heard and believed God in the first place.
βFor what saith the Scripture? Abraham believed God, and it was counted unto him for righteousness,β and thus βto him that worketh not, but believeth on Him that justifieth the ungodly, his faith is counted for righteousnessβ (Rom. 4:3,5).
The simplest, humblest believer, who ever so feebly commits himself to God and His Word, is βjustified freely by His grace through the redemption that is in Christ Jesusβ (Rom.Β 3:24). source