I’m not a scholar, but I don’t think you always have to be to work out how to behave in the world. Take for example the practice of wishing people “Merry Christmas.” I saw a post on Facebook the other day that said that when we say “Merry Christmas” we are essentially agreeing that Jesus was born on December 25th and because that’s not actual fact, we are committing shirk when we say it.
Does that mean that it wouldn’t be shirk if we knew exactly when Jesus was born and we wished people “Merry Christmas” then? Of course not. I think the real reason some Muslims think it’s not all right to acknowledge Christian holidays is because they’re afraid that 1) they’ll give non-Muslims the impression that they think the holidays are valid; or 2) that they’re acting like, or in danger of becoming, Christians just by wishing someone “Merry Christmas.”
Whenever I have trouble deciding how I feel about something, I look at it from a different angle. Usually that means putting myself in the opposite situation. What if I was a non-Muslim and a Muslim wished me “Merry Christmas”? Would I think, Oh, he must believe in Christmas! or would I be more likely to think that he is being friendly?
Or take it a step further: how do I react when a non-Muslim wishes me a Happy Eid? Do I think he is identifying with Islam or about to become a Muslim? Or do I see it as a friendly gesture, an acknowledgement of my religion and my right to express it?
The way I see it, the only time it’s shirk to wish someone a happy holiday is when they don’t know that you’re a Muslim. If you’re trying to pass as a non-Muslim or even a Christian, then that’s obviously shirk. But if it’s clear that you’re a Muslim, I don’t see any harm in it.
What if someone asks you if you believe in the Christmas Story? Then you would have the opportunity to tell him that while you don’t believe that Jesus is God, you do believe in the virgin birth and that Jesus was one of God’s greatest prophets. But I can’t see any upside to saying to someone, “I’d wish you Merry Christmas, but I think it’s all a lot of nonsense.”
That’s all Muslims need: to be seen as intolerant and dismissive of other religions. Our best witness is to show that we’re proud of being Muslims and to treat others the way God would have us treat them. And Allah is not a God of intolerance and discord.
Shirk is the act of assigning partners to Allah. Recognizing that others may be in error about monotheism is important, but it is our own acts of shirk that we need to be aware of. Belittling or ignoring non-Muslims will not bring them to the One God. It will only push them farther away.