To advance in spiritual life these things are essential, tapasya. Tapasya means voluntarily accepting something which may be painful. Just like we are recommending no illicit sex, no gambling, no meat-eating. So those who are accustomed to these bad habits, for them, in the beginning it may be a little difficult. But in spite of becoming difficult, one has to do it. That is called tapasya. To rise early in the morning, those who are not practiced, it is a little painful, but one has to do it. So this is called tapasya. So according to the Vedic injunction, there are some tapasyas that must be done. It is not, "I may do it or not do it." It must be done. Just like in the Muṇḍaka Upaniṣad it is ordered that one must go to the spiritual master. Tad-vijñānārthaṁ sa gurum evābhigacchet (MU 1.2.12). So there is no question of voluntarily, but it must be. And one must carry out by the order of a spiritual master and the order of the śāstra. That is called tapasya. Just like in our line ekādaśī is compulsory. One may feel some inconvenience fasting or simply eating fruits. No. It must be done. There are so many rules and regulation which is essential. It must be done. That is called tapasya. Without consideration whether it is convenient or inconvenient for you, which is, must be done, that is called tapasya.
Tapaḥ divyam... Just like Ṛṣabhadeva orders that this human life is meant for tapasya. Therefore in our Vedic civilization we find so many rules and regulations. This is tapasya. From the very beginning of life, brahmacārī, to go to the spiritual master's place and act like menial servant. Nīcavat, it is said. If the spiritual master says that "You go and pick up some wood from the forest," and one may be a king's son, but he cannot deny it, the spiritual master's order, "You must go," as Kṛṣṇa, He was ordered to go and pick up some dry wood from the forest. So He had to go. Although He was..., His father was Nanda Mahārāja, a village vaiśya king, and Kṛṣṇa was Personality of Godhead, but He could not deny. He had to go. Nīcavat. Just like menial servant. That is called brahmacārī. This is tapasya. So tapasya is so essential that one has to do it. There is no question of alternative.
Then brahmacārī, then..., if he marries, then gṛhastha. That is also tapasya. He cannot have sex life whenever he likes. No. The śāstra says, "You must have sex life like this: once in a month, and only for begetting children." So that is also tapasya. They do not follow..., people do not follow any tapasya at the present moment. But human life is meant for tapasya, regulative principles. Even in ordinary life... Just like you are driving your car, you are going to some urgent business, and you saw the red light. You have to stop. You cannot say, "I have to leave by this time. I must go." No. You must. That is tapasya. So tapasya means to follow the regulative principles strictly by the higher order. And that is human life. And animal life means you can do whatever you like. They keep to the right, keep to the left, it doesn't matter. But their offense is not taken, because they are animals. But a human being, if he does not follow the regulative principles, it is sinful. He'll be punished. The same principle: just like when there is red light, if you do not stop, you'll be punished. But a cat and dog, if he transgresses, "Never mind red light, I shall go," he's not punished. So tapasya is meant for the human being. He must do it if he wants at all progress of life. That is essential.