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

(31) And when Our Clear Verses are recited to them, those who disbelieve (the rich and strong among the pagans of Quraish who live a life of luxury) say to those who believe (the weak, poor companions of Prophet Muhammad صلى الله عليه وسلم who have a hard life): "Which of the two groups (i.e. believers or disbelievers) is best in (point of) position and as regards station (place of council for consultation)."

(32) "But whosoever turns away from My Reminder (i.e. neither believes in this Qur'an nor acts on its teachings.) verily, for him is a life of hardship, and We shall raise him up blind on the Day of Resurrection."

(33) That they may witness things that are of benefit to them (i.e. reward of Hajj in the Hereafter, and also some worldly gain from trade), and mention the Name of Allah on appointed days (i.e. 10th, 11th, 12th, and 13th day of Dhul-Hijjah), over the beast of cattle that He has provided for them (for sacrifice), [at the time of their slaughtering by saying: (Bismillah, Wallahu-Akbar, Allahumma Minka wa Ilaik).] Then eat thereof and feed therewith the poor having a hard time.

(34) That He (Allah) may make what is thrown in by Shaitan (Satan) a trial for those in whose hearts is a disease (of hypocrisy and disbelief) and whose hearts are hardened. And certainly, the Zalimun (polytheists and wrong-doers) are in an opposition far-off (from the truth against Allah's Messenger and the believers).

(35) And strive hard in Allah's Cause as you ought to strive (with sincerity and with all your efforts that His Name should be superior). He has chosen you (to convey His Message of Islamic Monotheism to mankind by inviting them to His religion of Islam), and has not laid upon you in religion any hardship: it is the religion of your father Ibrahim (Abraham) (Islamic Monotheism). It is He (Allah) Who has named you Muslims both before and in this (the Qur'an), that the Messenger (Muhammad صلى الله عليه وسلم) may be a witness over you and you be witnesses over mankind! So perform As-Salat (Iqamat-as-Salat), give Zakat and hold fast to Allah [i.e. have confidence in Allah, and depend upon Him in all your affairs]. He is your Maula (Patron, Lord), what an Excellent Maula (Patron, Lord) and what an Excellent Helper!

(36) Or [the state of a disbeliever] is like the darkness in a vast deep sea, overwhelmed with waves topped by waves, topped by dark clouds, (layers of) darkness upon darkness: if a man stretches out his hand, he can hardly see it! And he for whom Allah has not appointed light, for him there is no light.

(37) The sovereignty on that Day will be the true (sovereignty), belonging to the Most Gracious (Allah), and it will be a hard Day for the disbelievers (those who disbelieve in the Oneness of Allah - Islamic Monotheism).

(38) Verily, Allah knows those who believe, and verily, He knows the hypocrites [i.e. Allah will test the people with good and hard days to discriminate the good from the wicked, although Allah knows all that before putting them to test].

(39) As for those who strive hard in Us (Our Cause), We will surely guide them to Our Paths (i.e. Allah's religion - Islamic Monotheism). And verily, Allah is with the Muhsinun (good doers)."

(40) And We have enjoined on man (to be dutiful and good) to his parents. His mother bore him in weakness and hardship upon weakness and hardship, and his weaning is in two years - give thanks to Me and to your parents. Unto Me is the final destination.