In law, none is credited unless he is sworn. All facts must, when established by witnesses, be under oath or affirmation.

Explanation

(English-origin maxim.) No testimony is credited in legal proceedings unless given under oath or affirmation; unsworn declarations are not evidence and cannot establish any fact before the court.

Where this applies

• A neighbor tells the judge informally in the hallway that she saw the accident, but she never takes the stand or swears an oath — her statement can't be treated as evidence.
• A party submits a written statement from a friend supporting her claim, but the friend never signed it under oath — the unsworn statement has no evidentiary value.
• During a hearing, a spectator shouts out that the defendant is lying, but spectators aren't sworn witnesses — the court disregards the outburst entirely.