If duty required him to pay, he would do so.

Let them say, we stood where duty required us to stand.

But duty required that he report the message to the President.

For now, though, his duty required him to be here.

But she'd do either of those things and worse if duty required it.

Yet, sometimes duty requires of us more than we can bear.

If duty requires, we would try to shoot each other down.

"As for myself, I think my duty requires me to remain on board."

For now, his duty to the Empire required that he continue to act the part of a human.

They ought to know I will do what duty requires of me.