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

(11) Verily, those who believed, and emigrated and strove hard and fought with their property and their lives in the Cause of Allah as well as those who gave (them) asylum and help, - these are (all) allies to one another. And as to those who believed but did not emigrate (to you O Muhammad صلى الله عليه وسلم), you owe no duty of protection to them until they emigrate ; but if they seek your help in religion, it is your duty to help them except against a people with whom you have a treaty of mutual alliance; and Allah is the All-Seer of what you do.

(12) And those who believed, and emigrated and strove hard in the Cause of Allah (Al-Jihad), as well as those who gave (them) asylum and aid - these are the believers in truth, for them is forgiveness and Rizqun Karim (a generous provision i.e. Paradise).

(13) And those who believed afterwards, and emigrated and strove hard along with you (in the Cause of Allah), they are of you. But kindred by blood are nearer to one another (regarding inheritance) in the decree ordained by Allah. Verily, Allah is the All-Knower of everything.

(14) Do you think that you shall be left alone while Allah has not yet tested those among you who have striven hard and fought and have not taken Walijah [(Bitanah - helpers, advisors and consultants from disbelievers, pagans.) giving openly to them their secrets] besides Allah, and His Messenger, and the believers. Allah is Well-Acquainted with what you do.

(15) Do you consider the providing of drinking water to the pilgrims and the maintenance of Al-Masjidal-Haram (at Makkah) as equal to the worth of those who believe in Allah and the Last Day, and strive hard and fight in the Cause of Allah? They are not equal before Allah. And Allah guides not those people who are the Zalimun (polytheists and wrong-doers).

(16) Those who believed (in the Oneness of Allah - Islamic Monotheism) and emigrated and strove hard and fought in Allah's Cause with their wealth and their lives are far higher in degree with Allah. They are the successful.

(17) Say: If your fathers, your sons, your brothers, your wives, your kindred, the wealth that you have gained, the commerce in which you fear a decline, and the dwellings in which you delight are dearer to you than Allah and His Messenger, and striving hard and fighting in His Cause, then wait until Allah brings about His Decision (torment). And Allah guides not the people who are Al-Fasiqun (the rebellious, disobedient to Allah).

(18) March forth, whether you are light (being healthy, young and wealthy) or heavy (being ill, old and poor), and strive hard with your wealth and your lives in the Cause of Allah. This is better for you, if you but knew.

(19) O Prophet (Muhammad صلى الله عليه وسلم)! Strive hard against the disbelievers and the hypocrites, and be harsh against them, their abode is Hell, - and worst indeed is that destination.

(20) And when a Surah (chapter from the Qur'an) is revealed, enjoining them to believe in Allah and to strive hard and fight along with His Messenger, the wealthy among them ask your leave to exempt them (from Jihad) and say, "Leave us (behind), we would be with those who sit (at home)."