We are called marginal energy. We may be dark side or in the light side. So Krsna consciousness means to keep always in the light side. If we always think of Krsna, by chanting the Hare Krsna mantra, then we shall keep ourself on the light side. And as soon as we think of sense gratification, immediately we are on the dark side. We should be very cautious that we may not fall down on the dark side. We can keep ourself in the light side by nityam bhagavata-sevaya [SB 1.2.18]. Simply studying Srimad-Bhagavatam, Bhagavad-gita, try to understand, chanting Hare Krsna mantra. Twenty-four hours be engaged in this way. You'll be on the light side.

From Srila Prabhupada's lecture on Srimad-Bhagavatam 1.2.18 — Los Angeles, August 21, 1972