So the king, his duty was that if you are professing yourself as a brāhmaṇa, then it is the king's duty to see that you are acting as a brāhmaṇa. Brāhmaṇa is not by birth but guṇa-karma-vibhāgaśaḥ (BG 4.13). Guṇa means quality. And karma, and work also. Simply "I have got now sacred thread, I have become brāhmaṇa, doubly initiated; now my business is finished. I can work, I can do whatever we like, like less than śūdra, caṇḍāla." No, sir. If you are initiated as a brāhmaṇa, you must act as a brāhmaṇa. Truthfulness—satyaṁ śamo damas titikṣā ārjavaṁ jñānaṁ vijñānam āstikyaṁ brahma-karma (BG 18.42)—everything is there. A brāhmaṇa must be truthful. That is the first business of a brāhmaṇa—truthful. He'll speak truth even before an enemy. Nobody speaks truth before an enemy because he wants to hide something. But brāhmaṇa's business is to become truthful even before an enemy. That is stated.
There are many instances. Just like Satyakāma-jābāla, a boy, Satyakāma, he went to Gautama Muni: "Sir, I want to become your disciple." "Oh, very good. Are you brāhmaṇa or brāhmaṇa's son?" Formerly, in Vedic ways, nobody could be accepted as a disciple unless he's born in high class family, brāhmaṇa, kṣatriya, vaiśya—especially brāhmaṇa. So this question was asked, "Which family you belong to?" So he said, "I do not know what is my classification." "Now, who is your father?" "That I do not know." "Ask your mother." Then he went to his mother, "Who is my father?" "My dear boy, I do not know." So actually his mother was maidservant. So maidservants have so many men, and by whom she was pregnant she cannot remember. She also told the truth. And this Satyakāma, he also came to Gautama Muni, he said, "Sir, my father, my mother also do not know who is my father." "Oh, that's all right. You are a brāhmaṇa, because you are truthful. You do not hide yourself, that 'I am a prostitute's son.' You say this is the position. 'I am plainly speaking that my mother does not know who is my father. I do not know!' " So because he was truthful... That is the symptom of brāhmaṇa. He accepted, "Yes, I'll accept you as my disciple."