Sanskrit
काम एष क्रोध एष रजोगुणसमुद्भवः । महाशनो महापाप्मा विद्ध्येनमिह वैरिणम् ॥
kāma eṣa krodha eṣa rajoguṇasamudbhavaḥ mahāśano mahāpāpmā viddhy enam iha vairiṇam
Translation
It is desire, it is wrath, begotten by the quality of motion; all-consuming, all-polluting, know thou this as our foe here on earth.
Annie Besant · The Bhagavad-Gita, translated by Annie Besant (4th ed., 1922) — Wikisource · Public Domain
Explanation
Krishna’s answer names the enemy directly: kama, desire, identified with krodha, anger, and traced to rajas — the guna of motion and passion introduced back in verse 5’s mention of the gunas generally, now specified. Calling it “the foe” gives the rest of the chapter its final image: this isn’t an abstract flaw but an adversary to be fought, which is exactly the martial language verse 43 closes on.