From Tim Keller's The Reason for God: Belief in an Age of Skepticism
Christianity provides a firm basis for respecting people of other faiths. Jesus assumes that nonbelievers in the culture around them will gladly recognize much Christian behavior as "good" (Matthew 5:16; cf. 1 Peter 2:12). That assumes some overlap between the Christian constellation of values and those of any particular culture and of any other religion. Why would this overlap exist? Christians believe that all human beings are made in the image of God, capable of goodness and wisdom. The Biblical doctrine of the universal image of God, therefore, leads Christians to expect non-believers will be better than any of their mistaken beliefs could make them. The Biblical doctrine of universal sinfulness also leads Christians to expect believers will be worse in practice than their orthodox beliefs should make them. So there will be plenty of ground for respectful cooperation.
Christianity not only leads its members to believe that people of other faiths have goodness and wisdom to offer, it also leads them to expect that many will live lives morally superior to their own. Most people in our culture believe that, if there is a God, we can relate to him and go to heaven through leading a good life. Let's call this the "moral improvement" view. Christianity teaches the very opposite. In the Christian understanding, Jesus does not tell us how to live so we can merit salvation. Rather, he comes to forgive and save us through his life and death in our place. God's grace does not come to people who morally outperform others, but those who admit their failure to perform and who acknowledge their need for a Savior.