'Duty' in the Bible

Then Judah said to Onan, Go in to thy brother's wife, and fulfil to her the brother-in-law's duty, and raise up seed to thy brother.

If brethren dwell together, and one of them die, and have no son, the wife of the dead shall not marry a stranger abroad: her husband's brother shall go in unto her, and take her to him as wife, and perform the duty of a husband's brother unto her.

But if the man like not to take his brother's wife, his brother's wife shall go up to the gate unto the elders, and say, My husband's brother refuseth to raise up unto his brother a name in Israel: he will not perform for me the duty of a husband's brother.

And he left there, before the ark of the covenant of Jehovah, Asaph and his brethren, to do the service before the ark continually, as every day's duty required;

even as the duty of every day required, offering according to the commandment of Moses, on the sabbaths, and on the new moons, and at the set feasts, three times in the year, at the feast of unleavened bread, and at the feast of weeks, and at the feast of tabernacles.

And he appointed, according to the ordinance of David his father, the divisions of the priests for their service, and the Levites for their charges, to praise and serve before the priests, as the duty of every day required; and the doorkeepers by their divisions at every gate: for such was the commandment of David the man of God;

besides those from three years old and upward who as males were entered in the genealogical register, all that came into the house of Jehovah, as the duty of every day required, for their service in their charges, according to their divisions,

And they held the feast of tabernacles as it is written, and offered daily burnt-offerings by number, according to the ordinance, as the duty of every day required;

If there be a messenger with him, an interpreter, one among a thousand, to shew unto man his duty;