Definition & Meaning of "so help me (God)"

What is the origin of the idiom "so help me" and when to use it?

The origin of the phrase "so help me" can be traced back to the use of oaths and affirmations in legal and formal contexts. The addition of "so help me" serves as an appeal to a higher power, traditionally understood to be God, reinforcing the sincerity and gravity of the promise or statement being made. Over time, it has become a conventional expression in various solemn affirmations and pledges, both within and outside legal settings.