Tyāga means to give up the result to Kṛṣṇa. That is sannyāsa. Sat-nyāsa. Sat means the Supreme. And anyone who renounces everything for Kṛṣṇa, the Supreme, he is sannyāsī. That will be explained in the Fifth Chapter. Kāryaṁ karma karoti yaḥ. Anāśritaḥ karma-phalaṁ kāryaṁ karma karoti yaḥ, sa sannyāsī (BG 6.1). Kāryam, "It is my duty." Just like we have got in our institution specified duties for each and every member, and they are doing, and if . . . they take it seriously, every one of them, that it is the order and duty, "My Guru Mahārāja has specified this duty upon me. So it is my duty." Kāryam. Kāryam means "It is my duty. I must do it." So anāśritaḥ karma-phalaṁ kāryaṁ karma karoti . . . that he is trained up. According to varṇāśrama-dharma, that is trained up.
A brahmacārī, from the very beginning of his life, he is trained to act only for guru. That is brahmacārī. It is enjoined that a brahmacārī live at the shelter, at the care of guru just like a menial servant. Kṛṣṇa also, although He is the Supreme Personality of Godhead, when He was living as brahmacārī at His guru's house, Sāndīpani Muni, He was collecting wood, fuel, from the jungle. He was going daily. It is not that because He was Personality of Godhead, therefore He should not go. No. You will find in the Śrīmad-Bhāgavatam, Kṛṣṇa Book, that when Sudāmā Vipra met Him, he was talking with Him about His childhood stories. Kṛṣṇa reminded him, "Sudāmā, do you remember that one day we went to collect fuel for our Guru Mahārāja, and there was storm and rain, and we could not get out of the forest? We had to live overnight there. Then on the morning Guru Mahārāja came with other disciples and they recovered us from the jungle. Do you remember?" So Kṛṣṇa had to do this. This is training.
A brahmacārī is trained up from the very beginning how to become a sannyāsī at the end of life. How he is trained up? He is trained up to collect for guru alms. Everywhere the brahmacārī would go to householder, and they ask, "Mother, give us some alms for my Guru Mahārāja." And the ladies would give him. Because everyone's son goes to the gurukula. So there was no hesitation. And the brahmacārī would collect and bring it in the āśrama, and then he should live just like a menial servant. He may be a king's son or a very learned brāhmaṇa's son, but when he lives at gurukula, he has to work.