Musannaf Ibn Abi Shaybah 31015 — Book of the Judgments

Abu Sa'id al-A'sam said that the Messenger of Allah (peace and blessings be upon him) gave two rulings concerning a slave and his master. He ruled concerning the slave that when he comes out of the land of war before his master, he is free. Then, if the master comes out after the slave, the slave is not to be returned to him. And if the master comes out of the land of war before the slave, and the slave comes out after that, the slave is to be returned to the master.