make something one's duty

No one is quite sure when he made it his unofficial duty.

I had no further communication with Nigel for over a week but then made it my duty to seek him out in the Waterloo.

"But if you make this your duty, and harm comes to you, I'll go to my grave without forgiveness."

Cluny made it his duty to assess personally the progress at the tunnel workings.

His schools have managed to make their new duty to benefit the wider community remarkably undemanding.

It also made Picard's duty that much harder.

As we knew them, we made it our duty to arrange them, and in three hours his whole collection was labeled.

And given his mission orders, that made it his duty to attack it.

Nothing was clearer to Capek than the difference - which he made it his unflinching duty to point out.

The light cruisers made it their duty to seek out and destroy the somewhat dangerous scout ships.