The word(s) "duty" appears 33 time(s) in 31 verse(s) in Quran in Abdullah Yusuf Ali translation.

(21) To Him belongs whatever is in the heavens and on earth, and to Him is duty due always: then will ye fear other than Allah?

(22) But if they turn away, thy duty is only to preach the clear Message.

(23) Say: "Obey Allah, and obey the Messenger: but if ye turn away, he is only responsible for the duty placed on him and ye for that placed on you. If ye obey him, ye shall be on right guidance. The Messenger's duty is only to preach the clear (Message).

(24) "And if ye reject (the Message), so did generations before you: and the duty of the messenger is only to preach publicly (and clearly)."

(25) O mankind! do your duty to your Lord, and fear (the coming of) a Day when no father can avail aught for his son, nor a son avail aught for his father. Verily, the promise of Allah is true: let not then this present life deceive you, nor let the chief Deceiver deceive you about Allah.

(26) There can be no difficulty to the Prophet in what Allah has indicated to him as a duty. It was the practice (approved) of Allah amongst those of old that have passed away. And the command of Allah is a decree determined.

(27) "And our duty is only to proclaim the clear Message."

(28) "Lest the soul should (then) say: 'Ah! Woe is me!- In that I neglected (my duty) towards Allah, and was but among those who mocked!'-

(29) So He completed them as seven firmaments in two Days, and He assigned to each heaven its duty and command. And We adorned the lower heaven with lights, and (provided it) with guard. Such is the Decree of (Him) the Exalted in Might, Full of Knowledge.

(30) If then they run away, We have not sent thee as a guard over them. Thy duty is but to convey (the Message). And truly, when We give man a taste of a Mercy from Ourselves, he doth exult thereat, but when some ill happens to him, on account of the deeds which his hands have sent forth, truly then is man ungrateful!