It is narrated from Sayyidah Umm Salamah (may Allah be pleased with her) that the Messenger of Allah (peace and blessings be upon him) saw a slave boy of hers praying, and the Messenger of Allah (peace and blessings be upon him) said: "O Rabah, may your face be covered with dust."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20046