Mental purification (manaḥśuddhi) comes through dharma and adhyātmavidyā — knowledge of the inner Self. Ātmavidyā and dharma are received from father and ācārya, establishing again the crucial role of the teacher. The verse connects ethics (dharma), self-knowledge (ātmavidyā), and lineage — one cannot purify the mind through effort alone; one needs the transmission that comes through proper relationship.