Know that knowledge to be sattvic by which one sees a single, imperishable reality in all beings, undivided within what is divided.
Explanation
Krishna is now sorting knowledge into three kinds according to the three strands of nature (guṇa). Sattvic knowledge, the kind marked by clarity and balance (sattva), perceives one undivided, imperishable reality present in every being despite their outward differences. Advaita readings take this as the single Self (ātman) or Brahman; theistic traditions often take it as the same divine presence or the same kind of soul in all beings.