What is "so help me god"

phr. (n-g lang=en Used as an oath, a promise that an action will be carried out)

So help me God is a phrase often used to give an oath, and most commonly optional as part of an oath of office. It is also used in some jurisdictions as a form of oath for other forms of public duty, such as an appearance in court, service as a juror, etc.

The essence of the phrase is to emphasize that one means what one is saying or has said. It therefore implies greater care than usual in the act of the performance of one's duty, such as in testimony to the facts of the matter in a court of law.

The use of the phrase implies a greater degree of seriousness and obligation than is usually assigned to common conversation. See the discussion on oaths for more details.