everyone let him decide what to believe him. Why do something to try to prove to atheists? it is their opinion and choice, let them live as they want.
Because we love all people. We love atheists. We don't want to let atheists go to Hell without, at least, giving them a chance to repent. Of course, if they don't repent, Hell will probably be worse for them than if we had never talked to them.
but what about all the other gods? Gods from older religions? Were they wrong and false gods? What makes you think your god is the true one? Don't argue with religious fanatics, they will always use their holy book for "proof"
All gods are false gods in my book, you're talking to an atheist after all, I have no god.
To use an Andrew Dice Clay line, arguing with religious fanatics is like masturbating with a cheese grater, slightly amusing but mostly painful.
Jesus went through great pains to die on the cross to save people. Not believing Him is a slap in His face, and a great dishonor to Him. How much worse can you get than to dishonor the One Who is holding you so that you stay alive? Dishonoring and not believing Him is the worst act you can do.
I think you just need to not be hostile to those who do not support your opinion. You do not need to prove to atheists the existence of God, and to convince the faithful that God does not exist. Each is his own opinion.
We dont need to say harsh words to non believers nor curse them nor tell them they are wrong. Remember they are also God's CHildren, showing them God's existence is not by harsh words but by showing good deeds. Kindness and love, humility and the virtues that Christ has taught his Church are the virtues we must show to non-believers. If they practice these virtues they are still followers of Christ for they follow and aligned to GOd's will.