The word(s) "hard" appears 62 time(s) in 58 verse(s) in Quran in Muhammad Habib Shakir translation.

(31) Then there shall come after that seven years of hardship which shall eat away all that you have beforehand laid up in store for them, except a little of what you shall have preserved:

(32) The parable of those who disbelieve in their Lord: their actions are like ashes on which the wind blows hard on a stormy day; they shall not have power over any thing out of what they have earned; this is the great error.

(33) Yet surely your Lord, with respect to those who fly after they are persecuted, then they struggle hard and are patient, most surely your Lord after that is Forgiving, Merciful.

(34) Or some other creature of those which are too hard (to receive life) in your minds! But they will say: Who will return us? Say: Who created you at first. Still they will shake their heads at you and say: When will it be? Say: Maybe it has drawn nigh.

(35) Until when he reached (a place) between the two mountains, he found on that side of them a people who could hardly understand a word.

(36) So that He may make what the Shaitan casts a trial for those in whose hearts is disease and those whose hearts are hard; and most surely the unjust are in a great opposition,

(37) And strive hard in (the way of) Allah, (such) a striving as is due to Him; He has chosen you and has not laid upon you an hardship in religion; the faith of your father Ibrahim; He named you Muslims before and in this, that the Apostle may be a bearer of witness to you, and you may be bearers of witness to the people; therefore keep up prayer and pay the poor-rate and hold fast by Allah; He is your Guardian; how excellent the Guardian and how excellent the Helper!

(38) The kingdom on that day shall rightly belong to the Beneficent Allah, and a hard day shall it be for the unbelievers.

(39) He said: I desire to marry one of these two daughters of mine to you on condition that you should serve me for eight years; but if you complete ten, it will be of your own free will, and I do not wish to be hard to you; if Allah please, you will find me one of the good.

(40) And whoever strives hard, he strives only for his own soul; most surely Allah is Self-sufficient, above (need of) the worlds.