'Duty' in the Bible

I have a duty to perform and a debt to pay both to Greeks and to barbarians [the cultured and the uncultured], both to the wise and to the foolish.

As for us who are strong, our duty is to bear with the weaknesses of those who are not strong, and not seek our own pleasure.

It hath pleased them verily; and their debtors they are. For if the Gentiles have been made partakers of their spiritual things, their duty is also to minister unto them in carnal things.

So after discharging this duty, and making sure that these kind gifts reach those for whom they are intended, I shall start for Spain, passing through Rome on my way there;