The Mukhya Upaniṣads

Taittirīya · Vallī 1 · Anuvāka 11 · Taittirīya 1.11

Passage 4

ये यत्र ब्राह्मणाः संमर्शिनः ।युक्ता आयुक्ताः ।अलूक्षा धर्मकामाः स्युः ।यथा ते तत्र वर्तेरन् ।तथा वर्तेथाः ।अथाभ्याख्यातेषु ।ये तत्र ब्राह्मणाः संमर्शिनः ।युक्ता आयुक्ताः ।अलूक्षा धर्मकायाः स्युः ।यथा ते तेषु वर्तेरन् ।तथा तेषु वर्तेथाः ।एष आदेशः ।एष उपदेशः ।एषा वेदोपनिषत् ।एतदनुशासनम् ।एवमुपासितव्यम् ।एवमु चैतदुपास्यम् ॥ ४ ॥

In plain words

whatever brahmins there are who are thoughtful, apt, devoted, not harsh and lovers of what is right — as they conduct themselves in that matter, so shouldst thou conduct thyself. And with regard to those who are spoken against: whatever brahmins there are who are thoughtful, apt, devoted, not harsh and lovers of what is right — as they conduct themselves toward them, so shouldst thou conduct thyself toward them. This is the injunction, this is the instruction, this is the secret doctrine of the Veda, this is the command. Thus is it to be worshipped, and thus indeed is it to be practised.