Rule 603 Oath or Affirmation to Testify Truthfully

Before a witness can speak in court, they must make a formal promise to tell the truth. This can be a religious oath (like swearing on a Bible) or a non-religious affirmation, which is simply a solemn promise to be honest.

The goal is to make sure the witness understands that telling the truth is a serious obligation. The promise is meant to weigh on the witness's conscience, reminding them that lying in court has real consequences, including criminal charges for perjury.