I felt duty bound to help.

我觉得去帮忙是义不容辞的。

I'm duty bound to visit my old aunt.

我有义务赴探望年老的姑妈。

I'm duty bound to visit my old aunt.

我有义务去探望年老的姑妈。

He felt duty bound to take care of the old lady.

他觉得照顾那位老太太是他义不容辞的事情。

At accidents, every skier or snowboarder is duty bound to assist.

一旦遇见事故，每个滑雪者都有义务去帮助受伤的人。