Our prayers are often motivated by our own interests. Yet Jesus tells us to ask anyway. Mark 11:24 says, Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours. Notice that it says that you should believe it will be yours, not that it will be yours. Our faith needs to be that all things are possible through God, but in the end it must be according to His will, not our own selfish desires.