What is the ruling on someone who says "If only you had tried your luck" to a person who did something, and does this constitute disbelief (kufr)? What is the ruling on saying "Try your luck and do such-and-such"? Do Paradise and Hell worship Allah?

Statements that mention "luck" are permissible and do not constitute disbelief, because luck is the preordained share of everything. This is supported by the words of Allah Almighty: "But none is granted it except those who are patient, and none is granted it except one having a great portion [of good]" and His saying: "Allah instructs you concerning your children: for the male, what is equal to the share of two females."

As for Paradise and Hell, they are among the magnificent creations of Allah Almighty that glorify Him with His praise, as evidenced by His saying: "And there is not a thing except that it exalts [Allah] with praise, but you do not understand their [way of] exalting." It is known that Paradise is a abode of honor for the friends of Allah in the hereafter, and Hell is a abode of humiliation for His enemies therein.