The word(s) "heavy" appears 18 time(s) in 17 verse(s) in Quran in Mohsin Khan translation.

(1) And seek help in patience and As-Salat (the prayer) and truly it is extremely heavy and hard except for Al-Khashi'un [i.e. the true believers in Allah - those who obey Allah with full submission, fear much from His Punishment, and believe in His Promise (Paradise) and in His Warnings (Hell)].

(2) Thus We have made you [true Muslims - real believers of Islamic Monotheism, true followers of Prophet Muhammad صلى الله عليه وسلم and his Sunnah (legal ways)], a just (and the best) nation, that you be witnesses over mankind and the Messenger (Muhammad صلى الله عليه وسلم) be a witness over you. And We made the Qiblah (prayer direction towards Jerusalem) which you used to face, only to test those who followed the Messenger (Muhammad صلى الله عليه وسلم) from those who would turn on their heels (i.e. disobey the Messenger). Indeed it was great (heavy) except for those whom Allah guided. And Allah would never make your faith (prayers) to be lost (i.e. your prayers offered towards Jerusalem). Truly, Allah is full of Kindness, the Most Merciful towards mankind.

(3) O you who believe! Do not render in vain your Sadaqah (charity) by reminders of your generosity or by injury, like him who spends his wealth to be seen of men, and he does not believe in Allah, nor in the Last Day. His likeness is the likeness of a smooth rock on which is a little dust; on it falls heavy rain which leaves it bare. They are not able to do anything with what they have earned. And Allah does not guide the disbelieving people.

(4) And the likeness of those who spend their wealth seeking Allah's Pleasure while they in their ownselves are sure and certain that Allah will reward them (for their spending in His Cause), is the likeness of a garden on a height; heavy rain falls on it and it doubles its yield of harvest. And if it does not receive heavy rain, light rain suffices it. And Allah is All-Seer (knows well) of what you do.

(5) And the weighing on that day (Day of Resurrection) will be the true (weighing) . So as for those whose scale (of good deeds) will be heavy, they will be the successful (by entering Paradise).

(6) And it is He Who sends the winds as heralds of glad tidings, going before His Mercy (rain). Till when they have carried a heavy-laden cloud, We drive it to a land that is dead, then We cause water (rain) to descend thereon. Then We produce every kind of fruit therewith. Similarly, We shall raise up the dead, so that you may remember or take heed.

(7) Those who follow the Messenger, the Prophet who can neither read nor write (i.e. Muhammad صلى الله عليه وسلم) whom they find written with them in the Taurat (Torah) (Deut, xviii 15) and the Injeel (Gospel) (John xiv, 16) , - he commands them for Al-Ma'ruf (i.e. Islamic Monotheism and all that Islam has ordained); and forbids them from Al-Munkar (i.e. disbelief, polytheism of all kinds, and all that Islam has forbidden); he allows them as lawful At-Tayyibat (i.e. all good and lawful as regards things, deeds, beliefs, persons, foods), and prohibits them as unlawful Al-Khaba'ith (i.e. all evil and unlawful as regards things, deeds, beliefs, persons and foods), he releases them from their heavy burdens (of Allah's Covenant with the children of Israel), and from the fetters (bindings) that were upon them. So those who believe in him (Muhammad صلى الله عليه وسلم), honour him, help him, and follow the light (the Qur'an) which has been sent down with him, it is they who will be successful .

(8) They ask you about the Hour (Day of Resurrection): "When will be its appointed time?" Say: "The knowledge thereof is with my Lord (Alone). None can reveal its time but He. heavy is its burden through the heavens and the earth. It shall not come upon you except all of a sudden." They ask you as if you have a good knowledge of it. Say: "The knowledge thereof is with Allah (Alone), but most of mankind know not."

(9) It is He Who has created you from a single person (Adam), and (then) He has created from him his wife [Hawwa' (Eve)], in order that he might enjoy the pleasure of living with her. When he (a polytheist from Adam's offspring - as stated by Ibn Kathir in his Tafsir) had sexual relation with her (the polytheist's wife), she became pregnant and she carried it about lightly. Then when it became heavy, they both invoked Allah, their Lord (saying): "If You give us a Salih (good in every aspect) child, we shall indeed be among the grateful."

(10) 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.