Fire and Truth
Fire reveals truth - oaths were sworn over fire for this reason.
Fire's association with truth made it witness to oaths and ordeals. Ancient Persians swore oaths over fire, believing it would reveal falsehood. This reflects fire's role as symbol of Asha.
Let fire witness your oath, for it knows all truth.
Fire ordeal was used to determine guilt in ancient Persia.
Historical Practice
Written about in
- What Zoroastrianism says about truth and lying
Persians swore oaths over fire because fire was held to reveal falsehood; the oath was staged before a witness that could not be deceived. The practical effect was to make truth-telling a public, physical act rather than a private intention.