603 Oath or affirmation

Every witness who takes the stand must promise to tell the truth before they say anything else. This promise can be a formal oath or a simple affirmation, but either way it counts as a legal promise to be honest.

The words used don't have to follow an exact script. What matters is that the promise is serious enough to remind the witness they have a real duty to tell the truth. Courts want to make sure the witness understands they can't just say whatever they want, they have to be honest.

This rule applies to everyone who testifies, no matter their background or beliefs. As long as the oath or affirmation makes the witness feel bound to tell the truth, it meets the requirement.