Musar על נדרים 64:3

And the eye is the first entrance of the evil inclination, for through it there enters the heart the power of desire and lust against which we were exhorted at Mount Sinai, and as our sages of blessed memory said: "The eye sees, the heart desires and the instruments of action consummate." And, concerning this it was intimated (Eichah 3:51): "My eye scalds my soul more than all the daughters of my city." "my city" alludes to the powers of the body (which is also called guf [body]), as in Nedarim 32b: "'a small city' — this is the guf." The verse intimates that the eye has corrupted his soul more than all the other powers of the body, all of them coming to consummate only what his eyes have begun.