This was one of the early generations, may Allah have mercy on him.

He said he passed by a man and greeted him with salam, then was told he was a Christian.

Respond to my salam, just as I said. He said: Respond to my salam, because the Prophet ﷺ says: Do not initiate salam to the Jews and Christians.

Do not initiate salam to the Jews and Christians, meaning you can greet them with something other than salam.

You can say to him: Welcome, how are you, nice to see you.

Good morning, good evening, but do not say salam, because salam is one of the names of Allah the Blessed and Exalted, and he insults Allah.

Allah, the Blessed and Exalted, says: The son of Adam insults or curses the son of Adam.

He said, how is that possible? He said, he claims that I have a son, and the Christians say that Isa is the son of Allah.

So they insult Allah, the Exalted, so how can we come and say to them "peace"?

Upon you, these are the best of the disbelievers, meaning better than the Jews, better than the idol worshippers, better than the Buddhists, better than the Hindus, and even with that.

It is not allowed to initiate the greeting of peace to them, so others are even more so. If you must, for example, you enter his office and he is your boss at work.

May Allah grant you a good morning, welcome, nice to see you, how are you?

But you do not say "as-salamu alaykum."

Hold back from this, that's how it is for me. And if later you find out, you can tell him, respond to him, or you can remain silent.

The second time, he is not a Muslim, I mean.