So he said, "I do not know." "So go to your mother. Ask whose son you are." The mother said, "I do not know." So he came and he said that "Sir, my mother does not know whose son I am." So Gautama Muni accepted him as disciple because he was truthful. He saw that he has got the brahminical qualification, truthful. Everyone is not willing that to admit that he is the son of a prostitute. No. But he admitted, "Yes, my mother does not know by whom I was begotten." So this is qualification.
So in the Kali-yuga especially, there is no Vedic system of reformatory process. It is the pāñcarātriki-vidhi, that anyone has got a little qualification for becoming brāhmaṇa, he is accepted by the spiritual master and he is trained up, he is initiated, just to make him a complete brāhmaṇa. (reading:) "So the sacred thread is the sign of those who are competent to study the Vedas from ācārya, or the bona fide spiritual master." The bona fide spiritual master is called ācārya, or the ācārya can become a bona fide spiritual master. Ācārya means who knows the purport of the śāstra, and he behaves himself according to the shastric regulative principle and teaches his disciple in that way. He is called ācārya. Ācārya means whose behavior, whose activities should be followed. That is called ācārya.