इति गुह्यतमं शास्त्रमिदमुक्तं मयानघ | एतद्बुद्ध्वा बुद्धिमान्स्यात्कृतकृत्यश्च भारत ||
iti guhyatamaṁ śāstram idam uktaṁ mayānagha etad buddhvā buddhimān syāt kṛta-kṛtyaś ca bhārata
Translation
Thus this most secret scripture has been declared by Me, O sinless one. By knowing this, O Arjuna, one becomes enlightened and all duties are fulfilled.
Interpretation
Chapter 15 closes with Krishna calling the Purushottama teaching the 'most secret scripture' (guhyatamam shastram). Secret not because it is withheld but because it is subtler than anything that can be grasped by ordinary mind — it can only be received by one who has been prepared by purification and love. Knowing this truth — that Krishna is the Supreme Person, the ground of all being, dwelling in one's own heart — makes one buddhiman (truly intelligent, not just clever) and krita-kritya (one who has accomplished all that needed to be accomplished). In one realization, the entire purpose of human life is fulfilled.