Silsilat al-Ahadith al-Sahihah

It is narrated from Sayyiduna Ali (may Allah be pleased with him) that the Messenger of Allah (peace and blessings of Allah be upon him) sent an army and appointed a man as their commander. This commander lit a fire and said: "Enter into it." Some people (in obedience to the commander) actually intended to enter, while others said: "We accepted Islam in order to escape from the fire (and now...)." When this incident was reported to the Messenger of Allah (peace and blessings of Allah be upon him), he said to those who wanted to enter: "If you had entered the fire, you would have remained in it until the Day of Resurrection." And the Prophet (peace and blessings of Allah be upon him) praised the other people and said: "There is no obedience to any human being in disobedience to Allah; obedience is only in good deeds."