The mind of man is not morally depraved, but morally deprived; incapable of true morality. (redeeminggod.com)
I don't know if that qualifies as true morality if the only reason you don't commit evil deeds agaist your fellow man is because you might get caught and punished. (religion.blogs.cnn.com)
Since all thought presupposes an absolute (infinite), God can be known by thought, even apart from Christian revelation - if man can experience true morality! (faith.org.uk)