Rule 5.603 Oath or affirmation to testify truthfully

Before anyone can testify in court, they have to promise to tell the truth. This promise is either an oath or an affirmation, and both carry the same legal weight.

The point of this promise is to remind the witness how serious their testimony is. The words used don't have to be a specific religious oath. Courts allow different wordings, including non-religious affirmations, as long as the witness clearly understands they are making a serious commitment to be honest.

This matters because if a witness lies after making this promise, they can face criminal charges for perjury. The oath or affirmation is what makes their statements legally binding and sets the stage for holding them accountable if they don't tell the truth.