Musannaf Ibn Abi Shayba 7:490

Al-Fadl ibn Dukayn narrated to us, he said: Al-Hakam ibn Abd al-Rahman ibn Abi Na'm narrated to us, he said: Fatima bint Ali narrated to me, she said: My father said, from the Messenger of Allah (may Allah bless him and grant him peace): "Whoever frees a Muslim or believing soul, Allah will protect, for every limb of it, a limb of his from the Fire."