Sunan Ibn Majah, Chapter: The Book of Fasting

that the Messenger of Allah (saw) said: There are three whose supplications are not turned back: A just ruler, and a fasting person until he breaks his fast. And, the supplication of one who has been wronged is raised by Allah up to the clouds on the Day of Resurrection, and the gates of heaven are opened for it, and Allah says, 'By My Might I will help you (against the wrongdoer) even if it is after a while.'" Daif