Vimokṣa-niścaya: Pañcaśikha’s Analysis of Aggregates, Guṇas, and Tyāga (मोक्षनिर्णयः)
भीष्म उवाच दोषैर्मूलादवच्चिन्नैरविंशुद्धात्मा विमुच्यते । विनाशयति सम्भूतमयस्मयमयो यथा । तथा कृतात्मा सहजैदररषि्नश्यति तामसै:,भीष्मजीने कहा--राजन्! इन दोषोंका मूल कारण है अज्ञान। अत: मूलसहित इन दोषोंका नाश हो जानेपर मनुष्यका अन्त:ः:करण विशुद्ध होता है और वह संसार-बन्धनसे मुक्त हो जाता है। जैसे लोहेकी बनी हुई छेनीकी धार लोहमयी साँकलको काटकर स्वयं भी नष्ट हो जाती है, उसी प्रकार शुद्ध हुई बुद्धि तमोगुणजनित सहज दोषोंको नष्ट करके उनके साथ ही स्वयं भी शान्त हो जाती है
bhīṣma uvāca doṣair mūlād avacchinnair aviśuddhātmā vimucyate | vināśayati sambhūtam ayasmayam ayo yathā | tathā kṛtātmā sahajair doṣair naśyati tāmasaiḥ ||
Bhishma said: O King, when faults are cut off together with their root, the inner self—formerly impure—becomes purified and is released from worldly bondage. Just as an iron tool, itself made of iron, can sever an iron chain and in the process wear away, so too a disciplined and purified intellect destroys the innate, tamas-born defects; and having accomplished that destruction, it too becomes quieted and comes to rest.
भीष्म उवाच
Freedom comes when defects are removed along with their root-cause (ignorance/delusion). A purified, disciplined intellect can eliminate innate tamasic tendencies; once its task is done, even that corrective instrument becomes still, indicating the settling of mental activity after purification.
In the Śānti Parva instruction to Yudhiṣṭhira, Bhīṣma explains a method of inner purification: destroy faults at their source. He illustrates it with a simile—iron cutting iron—showing how a tool used to remove bondage may itself be worn away, paralleling how the refined intellect quiets after removing tamasic defects.