We just learned in the last section how Krishna chooses not to reveal Himself (nāhaṁ prakāśaḥ) to the unintelligent class (abuddhayaḥ), who sees Krishna’s form as a temporary manifestation of the unmanifest (avyaktaṁ vyaktim āpannaṁ). They remain covered by a curtain of illusion (yoga-māyā-samāvṛtaḥ). Hence, it is impossible for such foolish (mūḍha) thinkers to understand Krishna, especially His unborn (ajam) and imperishable (avyayam) nature. (BG 7.25)
Owing to His unborn and imperishable nature, Krishna knows the past (samatītāni), the present (vartamānāni) and the future (bhaviṣyāṇi), but we cannot know Krishna (māṁ tu veda na kaścana) by our own endeavors. (BG 7.26) We cannot know Krishna because all of us (sarva-bhūtāni) are born into delusion (sammohaṁ) characterized by dualities (dvandva-mohena), which are ultimately caused by (samutthena) our own desire (icchā) and hate (dveṣa). That is why Krishna emphasized the rarity of knowing Krishna twice in this chapter – once in general (BG 7.3) and the second time in the context of a knowledgeable (jñānavān) person (BG 7.19).
Krishna already gave the magic formula for escaping illusion – surrender unto Him alone (BG 7.14). But, how does one come to the stage of surrendering to Krishna alone and escape (nirmuktā) these dualities of delusion (dvandva-moha)? It is only possible for those pure souls (puṇya-karmaṇām) whose sinful actions (pāpaṁ) have been completely eradicated (anta-gataṁ) because of which they are engaged in devotional service (bhajante) of Krishna (māṁ) with determination (dṛḍha-vratāḥ). (BG 7.28)
There is a class of endeavoring transcendentalists (yatanti ) who take shelter of Krishna (mām āśritya) for the sake of getting liberated from the old age and death (jarā-maraṇa-mokṣāya). Owing to taking shelter of Krishna, they understand the entirety (kṛtsnam) of Brahman (spiritual existential reality), the Higher Self (adhyātmaṁ) and all actions (karma cākhilam). (BG 7.29)
With consciousness engaged with Krishna (yukta-cetasaḥ), those who know Krishna as the higher principle or the governing factor of material manifestation (adhibhūtā), divinity (adhidaivaṁ), and sacrifices (adhiyajñaṁ), know Krishna as the essence of everything even at the time of death. (BG 7.30) These statements are going to prompt Arjuna to ask a question at the beginning of the next chapter.
We can see here how understanding the Absolute Truth entails knowing Krishna and His energies, and knowing Krishna as the governing factor of all His energies.