Fiqh-us-Sunnah Volume 4, Funerals and Dhikr, Fiqh 4.113C.

Section : Supplication of a father, of one who is fasting, a traveller, and of a person who is wronged..

The Prophet, peace be upon him, said, “The supplications of three persons are accepted, and there is no doubt concerning their acceptance: the supplication of a father, of a traveller, and of one who is wronged.’ (Reported by Ahmad, Abu Daw’ud, and Tirmizhi, with a sound chain of transmitters)

The Prophet, peace be upon him, also said, “The supplications of three persons are not rejected: the supplication of a fasting person at the time of breaking fast, of a just ruler, and of a person who is wronged. Allah causes their supplications to rise above the clouds, and gates of heaven are opened for them, and God says, ‘By My Majesty, I will help you, even it be after a while’.” (Reported by Tirmizhi with a sound chain of authorities)