The word(s) "obligatory" appears 10 time(s) in 10 verse(s) in Quran in Mohsin Khan translation.

(1) Guard strictly (five obligatory) As-Salawat (the prayers) especially the middle Salat (i.e. the best prayer - 'Asr ) . And stand before Allah with obedience [and do not speak to others during the Salat (prayers)].

(2) It is He Who has sent down to you (Muhammad صلى الله عليه وسلم) the Book (this Qur'an). In it are Verses that are entirely clear, they are the foundations of the Book [and those are the Verses of Al-Ahkam (commandments), Al-Fara'id (obligatory duties) and Al-Hudud (legal laws for the punishment of thieves, adulterers)]; and others not entirely clear. So as for those in whose hearts there is a deviation (from the truth) they follow that which is not entirely clear thereof, seeking Al-Fitnah (polytheism and trials), and seeking for its hidden meanings, but none knows its hidden meanings save Allah. And those who are firmly grounded in knowledge say: "We believe in it; the whole of it (clear and unclear Verses) are from our Lord." And none receive admonition except men of understanding. (Tafsir At-Tabari).

(3) And let not those who covetously withhold of that which Allah has bestowed on them of His Bounty (Wealth) think that it is good for them (and so they do not pay the obligatory Zakat ). Nay, it will be worse for them; the things which they covetously withheld shall be tied to their necks like a collar on the Day of Resurrection . And to Allah belongs the heritage of the heavens and the earth; and Allah is Well-Acquainted with all that you do.

(4) And give to the women (whom you marry) their Mahr (obligatory bridal-money given by the husband to his wife at the time of marriage) with a good heart; but if they, of their own good pleasure, remit any part of it to you, take it, and enjoy it without fear of any harm (as Allah has made it lawful).

(5) Verily! As for those whom the angels take (in death) while they are wronging themselves (as they stayed among the disbelievers even though emigration was obligatory for them), they (angels) say (to them): "In what (condition) were you?" They reply: "We were weak and oppressed on the earth." They (angels) say: "Was not the earth of Allah spacious enough for you to emigrate therein?" Such men will find their abode in Hell - What an evil destination!

(6) And We brought the Children of Israel (with safety) across the sea, and they came upon a people devoted to some of their idols (in worship). They said: "O Musa (Moses)! Make for us an ilah (a god) as they have alihah (gods)." He said: "Verily, you are a people who know not (the Majesty and Greatness of Allah and what is obligatory upon you, i.e. to worship none but Allah Alone, the One and the Only God of all that exists)."

(7) To Him belongs all that is in the heavens and (all that is in) the earth and Ad-Din Wasiba is His [(i.e. perpetual sincere obedience to Allah is obligatory). None has the right to be worshipped but Allah)]. Will you then fear any other than Allah?

(8) Verily, the Muslims (those who submit to Allah in Islam) men and women, the believers men and women (who believe in Islamic Monotheism), the men and the women who are obedient (to Allah), the men and women who are truthful (in their speech and deeds), the men and the women who are patient (in performing all the duties which Allah has ordered and in abstaining from all that Allah has forbidden), the men and the women who are humble (before their Lord - Allah), the men and the women who give Sadaqat (i.e. Zakat, and alms), the men and the women who observe Saum (fast) (the obligatory fasting during the month of Ramadan, and the optional Nawafil fasting), the men and the women who guard their chastity (from illegal sexual acts) and the men and the women who remember Allah much with their hearts and tongues Allah has prepared for them forgiveness and a great reward (i.e. Paradise).

(9) Verily, your Lord knows that you do stand (to pray at night) a little less than two thirds of the night, or half the night, or a third of the night, and also a party of those with you. And Allah measures the night and the day. He knows that you are unable to pray the whole night, so He has turned to you (in mercy). So, recite you of the Qur'an as much as may be easy for you. He knows that there will be some among you sick, others travelling through the land, seeking of Allah's Bounty, yet others fighting in Allah's Cause. So recite as much of the Qur'an as may be easy (for you), and perform As-Salat (Iqamat-as-Salat ) and give Zakat, and lend to Allah a goodly loan. And whatever good you send before you for yourselves (i.e. Nawafil non-obligatory acts of worship: prayers, charity, fasting, Hajj and 'Umrah), you will certainly find it with Allah, better and greater in reward. And seek Forgiveness of Allah. Verily, Allah is Oft-Forgiving, Most-Merciful .

(10) Does man think that he will be left neglected (without being punished or rewarded for the obligatory duties enjoined by his Lord Allah on him)?