Sanskrit
इन्द्रियाणि मनो बुद्धिरस्याधिष्ठानमुच्यते । एतैर्विमोहयत्येष ज्ञानमावृत्य देहिनम् ॥
indriyāṇi mano buddhir asyādhiṣṭhānam ucyate etair vimohayaty eṣa jñānam āvṛtya dehinam
Translation
The senses, the mind and the Reason are said to be its seat; by these enveloping wisdom, it bewilders the dweller in the body.
Annie Besant · The Bhagavad-Gita, translated by Annie Besant (4th ed., 1922) — Wikisource · Public Domain
Explanation
Having named the enemy in verses 37-39, Krishna now maps its territory: senses, manas (mind), and buddhi (reason) are desire’s operating base. This is the same three-tier hierarchy verse 42 ranks in ascending order of subtlety, and naming the terrain here is what makes verse 41’s instruction — master the senses first — a targeted strategy rather than a vague exhortation.