The world is darkness; knowledge is light; but knowledge without truth is a mere shadow.
Ali ibn Abi TalibKnowledge is of two kinds: that which is absorbed and that which is heard. And that which is heard does not profit if it is not absorbed.
Ali ibn Abi TalibIf you find that somebody is not grateful for all that you have done for him, then do not get disappointed because often you will find that someone else feels under your obligation though you have done nothing for him and thus your good deeds will be compensated, and Allah will reward you for your goodness.
Ali ibn Abi Talib