गोविन्द भाष्य (श्रील बलदेव विद्याभूषण - अचिन्त्यभेदाभेद वेदान्त ब्रह्मसूत्र भाष्य सटीक)

"As a bird needs two wings to fly in the sky, so a man needs both Vedic rituals
and spiritual knowledge to attain liberation."
Or, perhaps spiritual knowledge alone is in truth the cause of liberation. After
all, the Śvetāśvatara Upaniṣad (3.8) declares:
tam eva viditvāti mṛtyum eti
"Only one who knows the Supreme Personality of Godhead can transcend the
bonds of birth and death."
After all is said and done it is not possible to reach a final conclusion in this
matter.
Siddhānta (conclusion): In the following words the author of the sūtras gives
His conclusion.
Sūtra 48
vidyaiva tu tan-nirdharaṇāt
vidyā—knowledge; eva—indeed; tu—certainly; tat—of that; nirdharaṇāt—
because of the conclusion.
It is knowledge indeed, for that is the conclusion.
Purport by Śrīla Baladeva Vidyābhūṣaṇa
The word "tu" (indeed) is used here to dispel doubt. Spiritual knowledge, and
not Vedic ritual, is the cause of liberation. Neither is it necessary that spiritual
knowledge be combined with the performance of Vedic rituals in order to bring
liberation. Why is that? The sūtra explains: "tan-nirdharaṇāt" (for that is the
conclusion). The conclusion is given in Śvetāśvatara Upaniṣad 3.8. The word
"vidyā" (knowledge) here means "the knowledge that leads to devotional service".
In the Bṛhad-āraṇyaka Upaniṣad (4.4.21) it is said:
vijñāya prajñāṁ kurvīta