Must a person give truthful testimony before a rabbinical court (beit din) even if doing so may cause him financial loss?

This source-based Torah study examines the question: Must a person give truthful testimony before a rabbinical court (beit din) even if doing so may cause him financial loss? The canonical Hebrew article develops the issue through the weekly Torah portion and the sources cited there. This localized discovery layer preserves the question and the source identity; it does not add any new halakhic, medical, legal, scientific, historical, theological, or empirical ruling or claim beyond the canonical Hebrew source.