The word(s) "duty" appears 132 time(s) in 121 verse(s) in Quran in Muhammad Pickthal translation.

(21) And if they argue with thee, (O Muhammad), say: I have surrendered my purpose to Allah and (so have) those who follow me. And say unto those who have received the Scripture and those who read not: Have ye (too) surrendered? If they surrender, then truly they are rightly guided, and if they turn away, then it is thy duty only to convey the message (unto them). Allah is Seer of (His) bondmen.

(22) And (I come) confirming that which was before me of the Torah, and to make lawful some of that which was forbidden unto you. I come unto you with a sign from your Lord, so keep your duty to Allah and obey me.

(23) Among the People of the Scripture there is he who, if thou trust him with a weight of treasure, will return it to thee. And among them there is he who, if thou trust him with a piece of gold, will not return it to thee unless thou keep standing over him. That is because they say: We have no duty to the Gentiles. They speak a lie concerning Allah knowingly.

(24) Wherein are plain memorials (of Allah's guidance); the place where Abraham stood up to pray; and whosoever entereth it is safe. And pilgrimage to the House is a duty unto Allah for mankind, for him who can find a way thither. As for him who disbelieveth, (let him know that) lo! Allah is Independent of (all) creatures.

(25) O ye who believe! Observe your duty to Allah with right observance, and die not save as those who have surrendered (unto Him)

(26) Allah had already given you the victory at Badr, when ye were contemptible. So observe your duty to Allah in order that ye may be thankful.

(27) O ye who believe! Devour not usury, doubling and quadrupling (the sum lent). Observe your duty to Allah, that ye may be successful.

(28) But those who keep their duty to their Lord, for them are Gardens underneath which rivers flow, wherein they will be safe for ever. A gift of welcome from their Lord. That which Allah hath in store is better for the righteous.

(29) O ye who believe! Endure, outdo all others in endurance, be ready, and observe your duty to Allah, in order that ye may succeed.

(30) O mankind! Be careful of your duty to your Lord Who created you from a single soul and from it created its mate and from them twain hath spread abroad a multitude of men and women. Be careful of your duty toward Allah in Whom ye claim (your rights) of one another, and toward the wombs (that bare you). Lo! Allah hath been a watcher over you.