Rule 603 Oath or Affirmation

Before you can testify in a Washington court, you must make a formal promise to tell the truth. This can be a traditional oath or an affirmation, which is a non-religious version of the same promise.

The goal is to make sure the witness understands the seriousness of what they are about to say. Lying under oath is a crime called perjury, so this step reminds witnesses of that responsibility before they speak.