What is the ruling on swearing by religion, and does that fall under swearing by other than Allah?

It is not permissible to swear an oath except by Allah, or by one of His Names, or by one of His Attributes. Swearing by other than Allah is a form of polytheism (shirk), such as swearing by religion. The Prophet (peace be upon him) forbade swearing by fathers, mothers, and rivals, and commanded that one should only swear by Allah, and should only swear by Allah if one is truthful. Swearing by obedience does not constitute an oath because it is swearing by other than Allah the Almighty.