श्री भगवानुवाच कालोऽस्मि लोकक्षयकृत्प्रवृद्धो लोकान्समाहर्तुमिह प्रवृत्तः। ऋतेऽपि त्वां न भविष्यन्ति सर्वे येऽवस्थिताः प्रत्यनीकेषु योधाः ॥

kālo ’smi loka-kṣhaya-kṛit pravṛiddho lokān samāhartum iha pravṛittaḥ ṛite ’pi tvāṁ na bhaviṣhyanti sarve ye ’vasthitāḥ pratyanīkeṣhu yodhāḥ

Time am I, laying desolate the world, Made manifest on earth to slay mankind! Not one of all these warriors ranged for strife Escapeth death; thou shalt alone survive.

In plain words: Krishna answers that he is Time, which destroys the world. He says none of the warriors gathered here will escape death, except Arjuna and his side.