Non-PRO English to Spanish Other Other Nouns

Buenas. Necesitaría que me ayuden con la expresión "work of plain and practical duty" que todavía no logro entender el significado, menos aún encontrar una traducción. Les dejo un poco de contexto.

"The keeping of the graves, then, was their work, the honoring gesture toward what was gone, the tending of its dirt remains, though they would not admit it, even to themselves. They regarded it as a work of plain and practical duty, they declared. "

Espero que me puedan ayudar.

Muchas gracias.