Mukhtasar Bukhari (Abridged) 1301 — Freeing and releasing prisoners

Abu Musa Ash'ari (may Allah be pleased with him) narrates from the Noble Prophet (peace and blessings of Allah be upon him) that the Messenger of Allah (peace and blessings of Allah be upon him) said: "Free the captive, feed the hungry, and visit the sick." (And it is obligatory to free a Muslim captive by whatever means possible.)