One should make his life successful by tapasya, austerity, penance. So brahmācārya is one of the items. Tapasya means beginning with brahmācārya, celibacy. Here we have given the meaning of tapasya: "by austerity or voluntary rejection of material enjoyment." Tapasā bramacaryeṇa. So tapasya. I do not like something to do because it is pleasing to me, but for the sake of my advancement of spiritual life I must have it. This is called tapasya. We prescribe four kinds of regulative principle: no illicit sex, no meat-eating, no gambling, no intoxication. In the Western countries these four things are very ordinary means of life. In the Western countries practically cent percent population, they are addicted to these sinful activities. So in our Society, anyone who joins, he has to accept these four principles of regulative life.
So brahmācārya, celibacy, sex, prohibition of sex life, especially illicit sex life . . . Unless one is married, no sex life is allowed. That is called brahmācārya. Tapasya begins with brahmācārya, life of celibacy, or accepting one wife only. That's all. Then śamena. Śamena, controlling the senses, controlling the mind. Śamena damena ca, these two things required. We should not become the servant of the mind; we should become master of the mind. And tyāgena. Tyāgena. Therefore in the śāstra the process of charity is recommended. In the Bhagavad-gītā it is also recommended that yajña-dāna-tapaḥ-kriya na tyājyaṁ kāryam eva tat (BG 18.5). Because I have renounced this world, it does not mean I shall give up the process of performing yajña, dāna and tapasya.