He said, the Messenger of Allah ﷺ said, "Whoever frees a slave, Allah will free a limb of his own body from the Fire for every limb of that slave."
حدثنا مكي بهذا الإسناد، وقال: أعتق الله بكل إرب منها إربا من النار.
Its chain of transmission is sahih. It has already been mentioned in 6265 and in many other places, and the hadith is found in the works of all the imams. See Bukhari 5/205, Muslim in the Book of Drinks 64, Abu Dawud 3687, Tirmidhi 1864, and Nasai 8/297. Hardly any book of hadith is without it.