Assalamu alaykum Sheikh, my non-Muslim friends say “good luck” before exams and I’m unsure if I can say it back. I know believing luck has power independent of Allah is shirk and I don’t believe that. Is saying it as a normal expression permissible? JazakAllahu khayran.

Ustadh AbdulAziz al-Haqqan

Don't fall into OCD and dig in too deep. When they say "good luck" in Arabic, the word is "hadhan." It is a dua to Allah to give you a great portion, and this is not haram.