It is narrated from Hazrat Ka'b bin Murrah (may Allah be pleased with him) that once I asked the Holy Prophet (peace and blessings be upon him), "At which part of the night is supplication most readily accepted?" The Holy Prophet (peace and blessings be upon him) replied, "In the last part of the night." And whoever frees a slave, Allah will free every limb of the one who frees from the Fire of Hell in exchange for every limb of the slave.