Am I required to offer expiation for an oath due to a slip of the tongue that inverted the hadith "There is no obedience to a creature in disobedience to the Creator," and due to my saying that Ibn Abbas (may Allah be pleased with them both) was from the People of the Book instead of from the Household of the Prophet (peace be upon him)?

Anger is a door to evil that leads to every ugliness, and it is not praised unless the sacred limits of Allah are violated. The Prophet, peace and blessings be upon him, advised against anger. A Muslim should restrain his tongue except for good or permissible speech. If a Muslim makes a mistake in his speech unintentionally due to intense anger, there is no sin upon him, as Allah Almighty says: "And there is no blame upon you for that in which you have erred, but [only for] what your hearts intended," and as in the hadith of the man who erred and said: "O Allah, You are my slave and I am Your Lord," he erred from extreme joy.