Abu Hurayrah (may Allah be pleased with him) said: Abu al-Qasim, the Prophet of repentance (peace and blessings be upon him), narrated to me: "Whoever accuses his slave who is innocent of what he said about him, the prescribed punishment will be carried out on that master on the Day of Resurrection, unless it is as he said."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النفقات / 15797