Tirmidhi

Explanation:
1:
It is understood from this that there is benefit in supplication (du'a). If, according to Allah’s will, it is accepted, then the thing that was asked for is given to the supplicant. And if, when the will (mashiyyah) is not for acceptance, then some calamity that was to befall in the future is averted from him in its place. Or, in the Hereafter, the Lord of the worlds will grant the supplicant a reward equivalent to that supplication. However, if the supplication is for a sin or against maintaining family ties (silat ar-rahm), then it is neither accepted nor is there any reward for it. Similarly, for the acceptance of supplication, it is also a condition that the supplication be appropriate to the person’s situation, and not beyond his natural state—such as a poor Indian praying, “O Allah, make me the president of America.”

Note:
(In the chain of narration, Ibn Luhay‘ah is weak, and Abu’z-Zubayr is a mudallis, but on the basis of corroborating evidences, this hadith is hasan.)