B.G 13.18

jyotiṣām api taj jyotis tamasaḥ param ucyate. jñānaṃ jñeyaṃ jñānagamyaṃ hṛdi sarvasya viṣṭhitam ॥18॥

The light that illuminates even the luminaries is said to be beyond darkness. He is knowledge, the knowable, and the goal of knowledge, situated in the heart of everyone.

Gīta Tātparya 13.18

'jñānagamyam' - is attained by the liberated through knowledge. He is said to be self-luminous, the one Purushottama, the best among the beings. The self-luminosity of beings is through self-knowledge and is possible only by His grace.

jñānena muktau prāpyatvāt jñānagamyam।

As it is attained by the liberated through knowledge, He is 'jñānagamyam', i.e. attainable by knowledge.

"svayameva ātmanā ātmānaṃ vettha" iti svajñeyatvāt jñeyam। anyajñeyatvasya "jñeyaṃ yat tat" iti pūrvameva siddhatvāt। kartṛkarmavirodhavādimataṃ nirākaroti uttarajñeyaśabdena।

The statement "By oneself, by the 'ātman', you know the 'ātman'" (10.15) indicates that it is knowable due to being self-known. The concept that "what is knowable is that" is already established as known by others. The doctrine opposing the relationship between subject and object is refuted by the subsequent 'jñeya', i.e. 'to know' word.

"svavettā vedanaṃ ca svaṃ svena vedyaśca keśavaḥ। parasya vettā vittiśca vedyaśca syāt paraiḥ kvacit॥ tatprasādaṃ vinā kaścinnaivaṃ vettuṃ hi śaknuyāt। svavedane'nyavittau vā nāsāvanyadapekṣate। svaprakāśa iti proktaḥ tenaikaḥ puruṣottamaḥ। jīvānāṃ svaprakāśatvaṃ tatprasādāt svavedanam॥"

"Lord Keshava is the knower of self and his own knowledge, and is to be known by his own self. Sometimes, the knower and knowledge of another may be known by others. Without his grace, no one can indeed know this. In self-knowledge or in other's knowledge, he does not depend on another. Thus, he is said to be self-luminous, the one Purushottama, the best among the beings. The self-luminosity of beings is self-knowledge by His grace."

iti ca।

- stated thus, as well.