
And it's not your DUTY,
because it's not your House.
Game of Thrones Season 1, Episode 6

And it's our DUTY
to assist the capital in time of need.
Game of Thrones Season 3, Episode 1

Go on, do your DUTY.
Game of Thrones Season 5, Episode 10

It's your DUTY to represent your House
when your father can't.
Game of Thrones Season 1, Episode 6

Even if he does, Sansa will do her DUTY.
Game of Thrones Season 2, Episode 3