यावत्सञ्जायते किञ्चित्सत्त्वं स्थावरजङ्गमम्।क्षेत्रक्षेत्रज्ञसंयोगात्तद्विद्धि भरतर्षभ॥
yāvat sañjāyate kiñcit sattvaṃ sthāvara-jaṅgamamkṣetra-kṣetrajña-sanyogāt tad viddhi bharatarṣabha
Word by word
The verse says
Whatever comes into being, Arjuna, moving or unmoving, know that it comes from the joining of the field and the one who knows the field.
In plain words
One sentence, and it covers everything that exists.
Nothing arises from the field alone. Nothing arises from the knower alone.
Saṃyogāt — from the joining. Everything that is anything is a meeting of the two.
Where you've felt this · in creative work
A song needs a singer and it needs the air in the room. Neither one of them is the song. Put the singer in a vacuum and there is nothing; leave the room empty and there is nothing. What you hear is not either thing, and it is not a third thing either.
Going deeper
Making everything a meeting rather than a product solves a problem the chapter created in verse 20.
If nature and the person are both beginningless, neither can be the source of the other, and the obvious question is where anything actually comes from. The answer here is that nothing comes from either. Things come from the joining — from a field being known.
That is a strange kind of causation and it is consistent with what the chapter has said about the pair all along.
For a reader it says something about your own existence that is easy to miss. You are not your body and you are not a soul temporarily parked in one. On this account you are the event of the two being together, which is why the chapter can insist both that you are not the field and that your life is entirely real.