Because we are not pure, these thoughts of sense gratification are bound to come into our mind, but if we do not act on them and keep ourselves always engaged in Krishna conscious activities, they will have no effect. Maya is always placing the memories of our past sinful activities before us, and encouraging us to come once again into her clutches, but by always chanting Hare Krishna and keeping our mind fixed on Krishna, he will give us the strength to resist her demands, and gradually they will diminish. Krishna is like the sun, and Maya is like darkness. Where there is sun what is the question of darkness?

From Srila Prabhupada's letter to: Koumadaki – Australia March 27, 1972