Sayyiduna Abu Hurayrah (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "Whichever Muslim frees a Muslim, Allah, in return, frees all of his limbs from the Fire of Hell."
(b) Sa'id bin Marjanah (may Allah have mercy on him) said: I heard this hadith and went with it to Ali bin al-Husayn (may Allah have mercy on him), and he went to a slave of his for whom Abdullah bin Ja'far (may Allah be pleased with them both) had offered him ten thousand dirhams or a thousand dinars, and he set him free.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العتق / 21306