The word(s) "duty" appears 64 time(s) in 61 verse(s) in Quran in Mohsin Khan translation.

(1) And if they had believed, and guarded themselves from evil and kept their duty to Allah, far better would have been the reward from their Lord, if they but knew!

(2) It is prescribed for you, when death approaches any of you, if he leaves wealth, that he makes a bequest to parents and next of kin, according to reasonable manners. (This is) a duty upon Al-Muttaqun (the pious - See V.2: 2).

(3) There is no sin on you, if you divorce women while yet you have not touched (had sexual relation with) them, nor appointed unto them their Mahr (bridal-money given by the husband to his wife at the time of marriage). But bestow on them (a suitable gift), the rich according to his means, and the poor according to his means, a gift of reasonable amount is a duty on the doers of good.

(4) And for divorced women, maintenance (should be provided) on reasonable (scale). This is a duty on Al-Muttaqun (the pious - See V.2:2).

(5) So if they dispute with you (Muhammad صلى الله عليه وسلم) say: "I have submitted myself to Allah (in Islam), and (so have) those who follow me." And say to those who were given the Scripture (Jews and Christians) and to those who are illiterates (Arab pagans): "Do you (also) submit yourselves (to Allah in Islam)?" If they do, they are rightly guided; but if they turn away, your duty is only to convey the Message; and Allah is All-Seer of (His) slaves .

(6) In it are manifest signs (for example), the Maqam (place) of Ibrahim (Abraham); whosoever enters it, he attains security. And Hajj (pilgrimage to Makkah) to the House (Ka'bah ) is a duty that mankind owes to Allah, those who can afford the expenses (for one's conveyance, provision and residence); and whoever disbelieves [i.e. denies Hajj (pilgrimage to Makkah), then he is a disbeliever of Allah], then Allah stands not in need of any of the 'Alamin (mankind, jinn and all that exists) .

(7) And to Allah belongs all that is in the heavens and all that is in the earth. And verily, We have recommended to the people of the Scripture before you, and to you (O Muslims) that you (all) fear Allah, and keep your duty to Him. But if you disbelieve, then unto Allah belongs all that is in the heavens and all that is in the earth, and Allah is Ever Rich (Free of all wants), Worthy of all praise.

(8) O you who believe! Do your duty to Allah and fear Him. And seek the means of approach to Him, and strive hard in His Cause (as much as you can), so that you may be successful.

(9) And obey Allah and the Messenger (Muhammad صلى الله عليه وسلم), and beware (of even coming near to drinking or gambling or Al-Ansab, or Al-Azlam, etc.) and fear Allah. Then if you turn away, you should know that it is Our Messenger's duty to convey (the Message) in the clearest way.

(10) The duty of the Messenger [i.e. Our Messenger Muhammad صلى الله عليه وسلم whom We have sent to you, (O mankind)] is nothing but to convey (the Message). And Allah knows all that you reveal and all that you conceal.