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

(51) Hastening to the inviter. The unbelievers shall say: This is a hard day.

(52) Has not the time yet come for those who believe that their hearts should be humble for the remembrance of Allah and what has come down of the truth? And that they should not be like those who were given the Book before, but the time became prolonged to them, so their hearts hardened, and most of them are transgressors.

(53) O you who believe! do not take My enemy and your enemy for friends: would you offer them love while they deny what has come to you of the truth, driving out the Apostle and yourselves because you believe in Allah, your Lord? If you go forth struggling hard in My path and seeking My pleasure, would you manifest love to them? And I know what you conceal and what you manifest; and whoever of you does this, he indeed has gone astray from the straight path.

(54) You shall believe in Allah and His Apostle, and struggle hard in Allah's way with your property and your lives; that is better for you, did you but know!

(55) O Prophet! strive hard against the unbelievers and the hypocrites, and be hard against them; and their abode is hell; and evil is the resort.

(56) Are you the harder to create or the heaven? He made it.

(57) And as to him who comes to you striving hard,

(58) O man! surely you must strive (to attain) to your Lord, a hard striving until you meet Him.