The word(s) "must" appears 38 time(s) in 31 verse(s) in Quran in Mohsin Khan translation.

(11) Say (O Muhammad صلى الله عليه و سلم): "This is my way; I invite unto Allah (i.e. to the Oneness of Allah - Islamic Monotheism) with sure knowledge, I and whosoever follows me (also must invite others to Allah i.e. to the Oneness of Allah - Islamic Monotheism with sure knowledge). And Glorified and Exalted be Allah (above all that they associate as partners with Him). And I am not of the Mushrikun (polytheists, pagans, idolaters and disbelievers in the Oneness of Allah; those who worship others along with Allah or set up rivals or partners to Allah)."

(12) [Lut (Lot)] said: "These (the girls of the nation) are my daughters (to marry lawfully), if you must act (so)."

(13) And they say: "Glory be to our Lord! Truly, the Promise of our Lord must be fulfilled."

(14) (They will enter) 'Adn (Eden) Paradise (everlasting Gardens), which the Most Gracious (Allah) has promised to His slaves in the Unseen: Verily His Promise must come to pass.

(15) There is not one of you but will pass over it (Hell): this is with your Lord; a Decree which must be accomplished.

(16) Then they debated one with another what they must do, and they kept their talk secret.

(17) And had it not been for a Word that went forth before from your Lord, and a term determined, (their punishment) must necessarily have come (in this world).

(18) And We shall set up balances of justice on the Day of Resurrection, then none will be dealt with unjustly in anything. And if there be the weight of a mustard seed, We will bring it. And Sufficient are We to take account.

(19) They said: "Who has done this to our alihah (gods)? He must indeed be one of the Zalimun (wrong-doers)."

(20) And for every nation We have appointed religious ceremonies, that they may mention the Name of Allah over the beast of cattle that He has given them for food. And your Ilah (God) is One Ilah (God - Allah), so you must submit to Him Alone (in Islam). And (O Muhammad صلى الله عليه وسلم) give glad tidings to the Mukhbitun (those who obey Allah with humility and are humble from among the true believers of Islamic Monotheism),