Who would Jesus want most to witness to a crowd of believers or a crowd of the as-yet unbelievers? If Jesus were to "feed the multitudes" in the crowd, what would he say to a Rabi who said "let me help you"? If you believe you are trying to let God's light shine through you, why would you intentionaly want to deny that light to anyone? Didn't Jesus teach you to be not afraid for God is with you?
In this time when all people with a Christian faith have such strong secular and cultural challenges to that faith, why would a Christian seek to lift-up, advance, promote, increase "Christian" differences which only come from different, but honestly different sectarian traditions?
Is that the kind of response you see Muslims make to any and every percieved slight against any Muslim?
Small hearts express themselves through small minds.
It seems to me the issue is not about doing something to "get you into heaven". The issue seems to be that as a person who believes you are saved, what do you do with your faith; what does God call you to do; ignore the poor in your community, or simply lend a helping hand with others? If your are saved, is your contribution "polluted" if it is co-mingled with contributions from the "unsaved", who had the same good intentions, good expression of their faith, as you did?
If you do not stand and present yourself, with your faith, openly, among people who have not come witness your faith, then who will? The only door you are closing is the door you shut your faith behind.