Some people spuriously find fault with the Shias because they swear by Prophet Muhammad, the Imams and by their progeny whereas swearing by any other than Allah is null and void.
No one has ever saidóeven from among our Sunni brothersóthat swearing by other than Allah is forbidden. It is something common among people to swear by anyone dear to them like their sons and others. How it would be forbidden when it has been mentioned many times in the Holy Qur’an? Allah says:
I swear by the fig and the olive and Mount Sinai and this city made secure. (Qur’an 95:1-3)
I swear by the soul and Him Who made it perfect. (Qur’an 91:7)
Of course, in the Sharia a legal oath (e.g an oath given in court or an oath on a legal document) by other than Allah or His attributes is not acceptable. This is a legal oath and anything other than this is considered to be only a manner of emphasizing a point.