श्री भगवानुवाचपरं भूयः प्रवक्ष्यामि ज्ञानानां ज्ञानमुत्तमम्। यज्ज्ञात्वा मुनयः सर्वे परां सिद्धिमितो गताः ॥

paraṁ bhūyaḥ pravakṣhyāmi jñānānāṁ jñānam uttamam yaj jñātvā munayaḥ sarve parāṁ siddhim ito gatāḥ

I will again proclaim that supreme Wisdom, of all wisdom the best, which having known, all the Sages have gone hence to the supreme Perfection.

In plain words: Krishna says he will explain again the highest wisdom, the best of all knowledge. Wise people who learned it reached the highest goal.