The word(s) "hard" appears 65 time(s) in 56 verse(s) in Quran in Mohsin Khan translation.

(21) But the Messenger (Muhammad صلى الله عليه وسلم) and those who believed with him (in Islamic Monotheism) strove hard and fought with their wealth and their lives (in Allah's Cause). Such are they for whom are the good things, and it is they who will be successful.

(22) And recite to them the news of Nuh (Noah). When he said to his people: "O my people, if my stay (with you), and my reminding (you) of the Ayat (proofs, evidence, verses, lessons, signs, revelations, etc.) of Allah is hard on you, then I put my trust in Allah. So devise your plot, you and your partners, and let not your plot be in doubt for you. Then pass your sentence on me and give me no respite.

(23) And Musa (Moses) said: "Our Lord! You have indeed bestowed on Fir'aun (Pharaoh) and his chiefs splendour and wealth in the life of this world, our Lord! that they may lead men astray from Your Path. Our Lord! Destroy their wealth, and harden their hearts, so that they will not believe until they see the painful torment."

(24) "Then will come after that, seven hard (years), which will devour what you have laid by in advance for them, (all) except a little of that which you have guarded (stored).

(25) Then, when they entered unto him [Yusuf (Joseph)], they said: "O ruler of the land! A hard time has hit us and our family, and we have brought but poor capital, so pay us full measure and be charitable to us. Truly, Allah does reward the charitable."

(26) For them is a torment in the life of this world, and certainly, harder is the torment of the Hereafter. And they have no Waq (defender or protector) against Allah.

(27) And for Allah that is not hard or difficult.

(28) Then, verily! Your Lord - for those who emigrated after they had been put to trials and thereafter strove hard and fought (for the Cause of Allah) and were patient, verily, your Lord afterward is, Oft-Forgiving, Most Merciful.

(29) "Or some created thing that is yet greater (or harder) in your breasts (thoughts to be resurrected, even then you shall be resurrected)." Then, they will say: "Who shall bring us back (to life)?" Say: "He Who created you first!" Then, they will shake their heads at you and say: "When will that be?" Say: "Perhaps it is near!"

(30) [Musa (Moses)] said: "Call me not to account for what I forgot, and be not hard upon me for my affair (with you)."