Sahih al-Bukhari Book 46, Hadith 9
The Prophet (ﷺ) sent Mu`adh to Yemen and said, "Be afraid, from the curse of the oppressed as there is no
screen between his invocation and Allah."
The Prophet (ﷺ) said, "Oppression will be a darkness on the Day of Resurrection."
Allah's Messenger (ﷺ) said, "Whoever has oppressed another person concerning his reputation or anything else, he should beg him to forgive him before the Day of Resurrection when there will be no money (to compensate for wrong deeds), but if he has good deeds, those good deeds will be taken from him according to his oppression which he has done, and if he has no good deeds, the sins of the oppressed person will be loaded on him."