مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3466
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated that Ibn ‘Abbas (رضي الله عنه) said: The Messenger of Allah (ﷺ) ruled concerning a mukatab (a slave who has a contract of manumission), if he is killed, the diyah of a free man should be paid, commensurate with how much of his contract of manumission he had paid off, and the rest should be paid as the diyah of a slave.
Musnad Ahmad 3489Its isnad is saheeh]