He reported God’s messenger as saying, “A servant is granted an answer provided he does not ask for anything sinful or for breaking ties of relationship, and provided he does not demand an answer quickly.” On being asked what demanding an answer quickly meant, God’s messenger replied, “It is when he says he has prayed and prayed and does not think he will be answered, so he grows weary in such circumstances and gives up supplication.”
He reported God’s messenger as saying, “When one of you makes supplication he must not say, ‘O God, forgive me if Thou wilt, but must be definite and cherish a great desire, for nothing which God gives is burdensome to Him.”
Abu Darda’ reported God’s messenger as saying, “A Muslim’s supplication for an absent brother receives an answer. An angel is stationed at his head, and as often as he makes supplication that his brother may be given what is good the angel who is put in charge of him says, ‘Amen, and may you receive the like’.”
He reported God's messenger as saying, “When one of you makes supplication he must not say, ‘O God, forgive me if Thou wilt, show mercy to me if Thou wilt, provide for me if Thou wilt’, but must make his request definite, for He does what He wills and there is no one to impose compulsion on Him.”