Jñāneśvarī (commentary on the Bhagavadgītā) 12.152

12.152

vāhūni āpulī āṇ |
dharī jo aṃtaḥkaraṇa |
niścayā sācapaṇa |
jayāceni ||

who, swearing an oath to himself, / controls his inner faculty, / and through whom resolve / attains truth;