The word(s) "duty" appears 86 time(s) in 79 verse(s) in Quran in Muhammad Habib Shakir translation.

(21) O you who believe! be patient and excel in patience and remain steadfast, and be careful of (your duty to) Allah, that you may be successful.

(22) O people! be careful of (your duty to) your Lord, Who created you from a single being and created its mate of the same (kind) and spread from these two, many men and women; and be careful of (your duty to) Allah, by Whom you demand one of another (your rights), and (to) the ties of relationship; surely Allah ever watches over you.

(23) And let those fear who, should they leave behind them weakly offspring, would fear on their account, so let them be careful of (their duty to) Allah, and let them speak right words.

(24) And whatever is in the heavens and whatever is in the earth is Allah's and certainly We enjoined those who were given the Book before you and (We enjoin) you too that you should be careful of (your duty to) Allah; and if you disbelieve, then surely whatever is in the heavens and whatever is in the earth is Allah's and Allah is Self-sufficient, Praise-worthy.

(25) O you who believe! do not violate the signs appointed by Allah nor the sacred month, nor (interfere with) the offerings, nor the sacrificial animals with garlands, nor those going to the sacred house seeking the grace and pleasure of their Lord; and when you are free from the obligations of the pilgrimage, then hunt, and let not hatred of a people-- because they hindered you from the Sacred Masjid-- incite you to exceed the limits, and help one another in goodness and piety, and do not help one another in sin and aggression; and be careful of (your duty to) Allah; surely Allah is severe in requiting (evil).

(26) They ask you as to what is allowed to them. Say: The good things are allowed to you, and what you have taught the beasts and birds of prey, training them to hunt-- you teach them of what Allah has taught you-- so eat of that which they catch for you and mention the name of Allah over it; and be careful of (your duty to) Allah; surely Allah is swift in reckoning.

(27) And remember the favor of Allah on you and His covenant with which He bound you firmly, when you said: We have heard and we obey, and be careful of (your duty to) Allah, surely Allah knows what is in the breasts.

(28) O you who believe! Be upright for Allah, bearers of witness with justice, and let not hatred of a people incite you not to act equitably; act equitably, that is nearer to piety, and he careful of (your duty to) Allah; surely Allah is Aware of what you do.

(29) O you who believe! remember Allah's favor on you when a people had determined to stretch forth their hands towards you, but He withheld their hands from you, and be careful of (your duty to) Allah; and on Allah let the believers rely.

(30) O you who believe! be careful of (your duty to) Allah and seek means of nearness to Him and strive hard in His way that you may be successful.