बलं बलवतां चाहं कामरागविवर्जितम्। धर्माविरुद्धो भूतेषु कामोऽस्मि भरतर्षभ ॥

balaṁ balavatāṁ chāhaṁ kāma-rāga-vivarjitam dharmāviruddho bhūteṣhu kāmo ’smi bharatarṣhabha

And I the strength of the strong, devoid of desire and passion. In beings I am desire not contrary to duty, O Lord of the Bharatas.

In plain words: Krishna says he is the strength of the strong when it is free from greed and passion. He is also the desire in people that does not go against what is right.