I'm a Christian and I feel I have more in common spiritually with other people of faith (particularly other People of the Book ie Abrahamic faiths) than people who have no or nominal faith. I will often say "God bless" (ie God Bless you") or "Gods hand is on X " to Christian friends/family, but would Muslim people be offended if I said this to them? I believe there is one God but different paths. I wonder if I should revert, as I whilst I love Jesus Christ as a prophet, a spiritual man committed to social justice in a time when people of faith were oppressed by pagans (Romans) I find it hard to believe the literal truth of the Virgin Birth and Resurrection (though I believe in them as powerful metaphors).
I work in the NHS with lots of Muslim colleagues. I have asked, and she was so kind and accepting and said she felt happy for me to say it, but I think she was speaking as a kind friend rather than theologically.