Mukhtasar Bukhari

Narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that when he set out with the intention of accepting Islam and his slave was with him (they became) separated from each other on the way. Afterwards, that slave returned at a time when he (Abu Hurairah) was sitting with the Noble Prophet (peace and blessings of Allah be upon him), so the Noble Prophet (peace and blessings of Allah be upon him) said: "O Abu Hurairah! Your slave has come back to you." So he said: I make you (peace and blessings of Allah be upon him) a witness that this slave is free. The narrator (Qais) says that this incident happened at the time when Sayyiduna Abu Hurairah (may Allah be pleased with him) was saying: "O beloved, though my night is hard and long... yet it delivered me from the abode of disbelief."