शमो दमस्तपः शौचं क्षान्तिरार्जवमेव च।ज्ञानं विज्ञानमास्तिक्यं ब्रह्मकर्म स्वभावजम्॥
śamo damas tapaḥ śaucaṃ kṣāntir ārjavam eva cajñānaṃ vijñānam āstikyaṃ brahma-karma svabhāva-jam
Word by word
The verse says
Calm, restraint, discipline, cleanness, patience, straightness, knowledge, judgement, and trust in what lies beyond: this is the work of the priestly kind, and it comes out of their nature.
In plain words
The first group, and what is listed is not a job.
Nine qualities. Calm, restraint, discipline, cleanness, patience, straightness, knowing, judging, and trusting.
Notice there is no mention of ritual, ceremony or payment. The work described is almost entirely a way of being, which is a strange thing to call an occupation.
Where you've felt this · in study
A retired schoolteacher in your area is the person families go to when there is a dispute about land. He has no authority and charges nothing. People go because he will listen to both sides for an hour without interrupting, and because in forty years nobody has known him to repeat what was said in that room.
Going deeper
Describing a role entirely in terms of character rather than activity is what makes this list unusual.
Every item is something you are rather than something you do. Calm, patience, straightness. There is no task here that could be put on a schedule, which means this work cannot be performed by someone who has not become a particular kind of person.
That is also the strongest internal argument against the hereditary reading. If the work is the nine qualities, then someone born into the group who has none of them is not doing the work, whatever his name is, and someone outside it who has all nine is.
For an ordinary reader the list is most useful read as a description rather than a category. These nine are what you would want in anyone you went to for a judgement, including a friend. Most people can name someone who has them, and that person is almost never the one with the title.