Brāhmin means there is no sinful activity. All your pious life. Satyaṁ śaucam . . . satyaṁ, śaucam, āstikyam, jñānaṁ, vijñānam, śamo, dama (SB 1.16.26)—these are the qualification. Satyaṁ means a brāhmin is truthful, and he's controlling the mind, he's controlling the senses. Śamo dama titikṣa: he's tolerant, and ārjavam, he's very simple. Life is very simple. Jñānaṁ—full of knowledge; vijñānaṁ—practical application of knowledge in life; and āstikyam—believer, not unbeliever; believer in the existence of God. These are the qualification of brāhmin.
So the more one becomes sinful, he becomes degraded more and more. Therefore there are divisions of the society. That should be. Unless human society it will be divided into the principles, as they are spoken by Kṛṣṇa:
- cātur-varṇyaṁ mayā sṛṣṭaṁ
- guṇa-karma-vibhāgaśaḥ
- (BG 4.13)
Guna-karma: according to quality and work. Just like if you are qualified medical practitioner, you have passed the medical examination, that is your quality. But you must practice also as a medical man; then people will call you as physician. If you simply pass your medical examination and sit down at home, nobody will call you physician. When you practically engage yourself in medical business, then people will call you physician.