'Duty' in the Bible

Therefore, brethren, pick out from among yourselves seven men of good repute, full of the Spirit and of wisdom, and we will appoint them to undertake this duty.

Now when Herod was on the point of taking him out of prison, that very night Peter was asleep between two soldiers, bound with two chains, and guards were on duty outside the door.

"And now, impelled by a sense of duty, I am on my way to Jerusalem, not knowing what will happen to me there,

But even the sacrifice of my life I count as nothing, if only I may perfect my earthly course, and be faithful to the duty which the Lord Jesus has entrusted to me of proclaiming, as of supreme importance, the Good News of God's grace.

"I myself, however, thought it a duty to do many things in hostility to the name of Jesus, the Nazarene.