परं भूयः प्रवक्ष्यामि ज्ञानानां ज्ञानमुत्तमम्।यज्ज्ञात्वा मुनयः सर्वे परां सिद्धिमितो गताः॥
paraṃ bhūyaḥ pravakṣyāmi jñānānāṃ jñānam uttamamyaj jñātvā munayaḥ sarve parāṃ siddhim ito gatāḥ
Word by word
The verse says
Krishna said: I will tell you again the highest knowledge, the best of all knowing — knowing which, all the sages went from here to the highest completion.
In plain words
Bhūyaḥ — again. He has said this before and is saying it again.
The three strands have come up in chapters 3, 7 and 13 without being set out properly.
This chapter is where the subject finally gets its own treatment.
Where you've felt this · in study
A teacher has mentioned the same idea in passing four times across a term. Then one week she stops, puts down the chalk, and says: right, this one properly. The class sits up, because they have heard the words before and know they never quite caught them.
Going deeper
Returning to something already mentioned several times is a sign that the earlier mentions were not enough, and the chapter says so in its first word.
The three strands have been doing work in this book since Chapter 3, where they were named as what actually performs action. Chapter 7 said all three come from him and that he is not in them. Chapter 13 listed them as born of nature. None of those passages explained what they are.
This chapter does, and it is the reference that the rest of the book, including Chapter 18, leans on.
For a reader that makes this a chapter worth slowing down in. The vocabulary set here — three ways that everything in nature can be weighted — gets used from here to the end, and the final chapter in particular is almost unreadable without it.