Because we want something sublime and yet want it cheaply, we put ourselves in a position to be cheated. This means that we actually want to be cheated. If we want something valuable, we must pay for it. We cannot expect to walk into a jewelry store and demand the most valuable jewel for a mere ten cents. No, we must pay a great deal. Similarly, if we want perfection in yoga, we have to pay by abstaining from sex. Perfection in yoga is not something childish, and Bhagavad-gita instructs us that if we try to make yoga into something childish, we will be cheated. There are many cheaters awaiting us, waiting to take our money, giving us nothing, and then leaving. But according to Sri Krsna’s authoritative statement in Bhagavad-gita, one must be “completely free from sex life.” Being free from sex, one should “meditate upon Me within the heart and make Me the ultimate goal of life.” This is real meditation.

From The Path of Perfection, by Srila Prabhupada