But it does no good to tell someone Jesus is the savior when the person has no idea what they need saving from. They need to know that God created everything, that he has standards of righteousness, and that everyone has failed to live up to his righteous standards. They explaining what Jesus did for them makes sense. Until they know these things, it doesn't make sense to people.
It used to be that almost all Americans had the biblical background, but it isn't true anymore. This makes witnessing harder, but also might make people more likely to accept their need of a savior once it is explained because it is new instead of the same condition they have lived with their whole lives.
Paul witnessed to Greeks in a different manner than Hebrews because the Hebrews had the foundation and the Greeks didn't. The basis for everything in the New Testament is in Genesis.
