पुरोधसां च मुख्यं मां विद्धि पार्थ बृहस्पतिम्।सेनानीनामहं स्कन्दः सरसामस्मि सागरः॥
purodhasāṃ ca mukhyaṃ māṃ viddhi pārtha bṛhaspatimsenānīnām ahaṃ skandaḥ sarasām asmi sāgaraḥ
Word by word
The verse says
Among household priests know me, Arjuna, as the chief of them, Bṛhaspati. Among commanders I am Skanda. Among waters, the ocean.
In plain words
Three roles, three chiefs.
The priest a household depends on. The commander an army depends on. And then the ocean, which is not a person at all.
The pattern is holding, and the items keep sliding between people and things.
Where you've felt this · at work
Your office has somebody whose job title explains almost nothing about what she does. She was away for a week last year. Three separate things stopped working and nobody could say exactly why. The organisation chart has her name in a small box near the bottom.
Going deeper
Two of the three items here are chiefs of people, and the third is the thing all water ends up in, which is a different sort of first.
The ocean is not the best water. It is where water goes, and what every river is on its way to becoming. Putting it in a list with a chief priest and a commanding general quietly broadens what being foremost can mean — not only the top of a hierarchy but also the end of a direction.
Chapter 2 used the same image for a very different purpose, saying that desires enter a steady person as rivers enter the sea, which is full and unmoved.
So the item carries more than rank. It suggests that one way of being the greatest of a class is to be the thing all the others are heading toward without knowing it, and to be undisturbed by their arrival.