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

(11) Beautified is the life of the world for those who disbelieve; they make a jest of the believers. But those who keep their duty to Allah will be above them on the Day of Resurrection. Allah giveth without stint to whom He will.

(12) And make not Allah, by your oaths, a hindrance to your being righteous and observing your duty unto Him and making peace among mankind. Allah is Hearer, Knower.

(13) When ye have divorced women, and they have reached their term, then retain them in kindness or release them in kindness. Retain them not to their hurt so that ye transgress (the limits). He who doeth that hath wronged his soul. Make not the revelations of Allah a laughing-stock (by your behaviour), but remember Allah's grace upon you and that which He hath revealed unto you of the Scripture and of wisdom, whereby He doth exhort you. Observe your duty to Allah and know that Allah is Aware of all things.

(14) Mothers shall suckle their children for two whole years; (that is) for those who wish to complete the suckling. The duty of feeding and clothing nursing mothers in a seemly manner is upon the father of the child. No-one should be charged beyond his capacity. A mother should not be made to suffer because of her child, nor should he to whom the child is born (be made to suffer) because of his child. And on the (father's) heir is incumbent the like of that (which was incumbent on the father). If they desire to wean the child by mutual consent and (after) consultation, it is no sin for them; and if ye wish to give your children out to nurse, it is no sin for you, provide that ye pay what is due from you in kindness. Observe your duty to Allah, and know that Allah is Seer of what ye do.

(15) It is no sin for you if ye divorce women while yet ye have not touched them, nor appointed unto them a portion. Provide for them, the rich according to his means, and the straitened according to his means, a fair provision. (This is) a bounden duty for those who do good.

(16) For divorced women a provision in kindness: a duty for those who ward off (evil).

(17) The guiding of them is not thy duty (O Muhammad), but Allah guideth whom He will. And whatsoever good thing ye spend, it is for yourselves, when ye spend not save in search of Allah's Countenance; and whatsoever good thing ye spend, it will be repaid to you in full, and ye will not be wronged.

(18) O ye who believe! Observe your duty to Allah, and give up what remaineth (due to you) from usury, if ye are (in truth) believers.

(19) O ye who believe! When ye contract a debt for a fixed term, record it in writing. Let a scribe record it in writing between you in (terms of) equity. No scribe should refuse to write as Allah hath taught him, so let him write, and let him who incurreth the debt dictate, and let him observe his duty to Allah his Lord, and diminish naught thereof. But if he who oweth the debt is of low understanding, or weak, or unable himself to dictate, then let the guardian of his interests dictate in (terms of) equity. And call to witness, from among your men, two witnesses. And if two men be not (at hand) then a man and two women, of such as ye approve as witnesses, so that if the one erreth (through forgetfulness) the other will remember. And the witnesses must not refuse when they are summoned. Be not averse to writing down (the contract) whether it be small or great, with (record of) the term thereof. That is more equitable in the sight of Allah and more sure for testimony, and the best way of avoiding doubt between you; save only in the case when it is actual merchandise which ye transfer among yourselves from hand to hand. In that case it is no sin for you if ye write it not. And have witnesses when ye sell one to another, and let no harm be done to scribe or witness. If ye do (harm to them) lo! it is a sin in you. Observe your duty to Allah. Allah is teaching you. And Allah is knower of all things.

(20) If ye be on a journey and cannot find a scribe, then a pledge in hand (shall suffice). And if one of you entrusteth to another let him who is trusted deliver up that which is entrusted to him (according to the pact between them) and let him observe his duty to Allah his Lord. Hide not testimony. He who hideth it, verily his heart is sinful. Allah is Aware of what ye do.