Romans is the longest and most systematically reasoned of Paul's letters. Paul announces its theme in 1:16-17: the gospel is God's power for salvation, because it shows us that the righteousness of God is through faith for all who believe. Paul explains the need for justification through faith because of sin (1:16-4:25). He then spells out the results of justification by faith in terms of both present experience and future hope (5:1-8:39). In the next three chapters, he expresses his sorrow that many of his fellow Israelites have not embraced the gospel, and he wrestles with the theological implications of this (chs. 9-11). He concludes by describing how the gospel should affect one's everyday life (chs. 12-16). Paul wrote his letter to Rome in about a.d. 57.