Is it okay to say good luck?

Answer:


“I would advise you not to say “good luck” and the idea of luck is not really considered to be al-fa’al but rather luck is what people believe in when they don’t believe in blessings from Allaah ta aa’la. They have money, they have good things happen to them and they believe in good luck and so they seek to increase themselves in good luck by charms or by belief in different things and they think that this is the source of their blessings and this is all shirk and very despicable habits to not praise the One who has given you something, to not thank the One who has bestowed a great blessing upon you and say “I’m lucky.” This is filthy and this is disgusting and I know that the questioner is not asking about that situation, but yet that is the basis of the practice of saying “good luck.” Its from those people who have those belief, so let us be distinct from them and have good words and good phrases about Allaah, let us not pass up an opportunity in front of another Muslim or in front of a kaafir, to praise Allaah for what we have. Even if you are talking to a kafir and you have to mention something about your family, or about your wealth, or about your car, say: “This is from Allaah the Lord of the Creation who has given this to me, and its not from my work and my efforts but instead its a blessing from Allaah. I’m not a lucky person, rather I’m a blessed person, with blessings from Allaah” ...and in that you become a daa’ee as opposed to saying “I’m lucky,” you become a person who’s speech is similar to the speech of the people of shirk.”
                                                                                            
                                                                          taken from: http://salaf-us-saalih.com/page/2/