It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that on the day of Ta'if two slaves came out while the Prophet (peace and blessings be upon him) was besieging them, so the Messenger of Allah (peace and blessings be upon him) set them both free.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12040