p. 266
एवं वेदानां वेदनरूपात्मप्रतिपादनप्रकारं मयोक्तं योऽभिविजानाति, स जानाति परं हि तत् परं ब्रह्म जानाति इत्येव ।यो हि पाण्डित्यं निर्विद्य व्यवस्थितः, सः क्षिप्रं बाल्यादिकं निर्विद्य ब्राह्मणो भवतीत्यर्थः ॥
In plain words
So: whoever fully grasps what I have laid out — the way the Vedas set forth the Self, whose very nature is knowing — that one knows. And "he knows that supreme" means exactly this and no more: he knows the supreme Brahman. For the one who has lost all appetite for scholarship and stands steady there soon loses his appetite for childlike simplicity and the stages after it as well, and becomes a brāhmaṇa. That is the sense of it.
Close to the Sanskrit
Thus, whoever fully knows the manner of the Vedas' expounding of the Self whose nature is knowing — the manner stated by me — he knows; 'he indeed knows that supreme' means just this: he knows the supreme Brahman. For he who, having become indifferent to learnedness, stands firmly established — he, quickly becoming indifferent to childlikeness and the stages that follow, becomes a brāhmaṇa: this is the meaning.