If someone sees another person violating a prohibition and does not stop him, does he violate 'Do not place a stumbling block before the blind'?

This source-based Torah study examines the question: If someone sees another person violating a prohibition and does not stop him, does he violate 'Do not place a stumbling block before the blind'? The canonical Hebrew discussion develops the issue through the weekly Torah portion and the classical sources cited there, preserving the distinctions and tensions of the original unit. This localized layer is a discovery-oriented summary rather than a full translation of the article, and it does not add a new halakhic, medical, legal, historical, mystical or empirical ruling or claim beyond the canonical source. Any practical conclusion remains subject to the unit’s canonical review status.