Musannaf Ibn Abi Shaybah 35845 — A slave who leaves dar al-harb before

It is narrated from Abu Sa'id al-A'sam that the Prophet (peace and blessings be upon him) gave two judgments concerning a slave and his master: if the slave leaves the land of war before his master, he is free, and if his master then comes afterwards, the slave is not returned to him; and if the master comes out of the land of war before the slave and the slave comes after him, the slave is given back to his master.