p. 274
आद्यां विद्यां वदसि हि सत्यरूपां या प्राप्यते ब्रह्मचर्येण सद्भिः ।
In plain words
What you are speaking of is the first knowledge, the one whose very substance is truth — the knowledge good people reach by living brahmacarya.
Close to the Sanskrit
You speak indeed of the primal knowledge, whose form is truth, which is attained by the good through brahmacarya.