It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: The supplication of the oppressed is surely accepted, even if he is a sinner and immoral, because his sinfulness and immorality concern only himself.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 8795