ज्योतिषामपि तज्ज्योतिस्तमसः परमुच्यते।
ज्ञानं ज्ञेयं ज्ञानगम्यं हृदि सर्वस्य विष्ठितम्।।13.18।।
।।13.18।। (वह ब्रह्म) ज्योतियों की भी ज्योति और (अज्ञान) अन्धकार से परे कहा जाता है। वह ज्ञान (चैतन्यस्वरूप) ज्ञेय और ज्ञान के द्वारा जानने योग्य (ज्ञानगम्य) है। वह सभी के हृदय में स्थित है।।
Since the Supreme Lord Krishna is achieved by experiencing spiritual knowledge, He is understood to be the goal of all knowledge. Know the atma or immortal soul by experiencing the atma. As the Supreme Lord is the bestower of the atma and the atma is only knowable through Him then He is the most worthy object of knowledge. If the Supreme Lord is knowable by other means then the words He spoke earlier in verse 13 jneyam yat tat meaning all that which is worth knowing would make this verse repetitive. Now He affirms here the means to achieve what He revealed as the goal in verse 13 negating any contradiction. The Supreme Lord knows Himself by His Self alone. His knowing is not dependent on any external source outside of Himself. In special cases He is able to be known by others as it is possible to know Him by His desire and also by realization of the atma. But only by His grace can this manifest and without His grace knowledge of Him can never manifest. The Supreme Lord is self illuminated, He is self contented and He is equal towards all. Therefore as He is the foremost of all, He is the object of attainment for all and all jivas or embodied beings should seek His grace for only by His grace can He be known.