The word(s) "monotheism" appears 283 time(s) in 267 verse(s) in Quran in Mohsin Khan translation.

(21) But those who believe (in the Oneness of Allah - Islamic monotheism) and do deeds of righteousness, We shall admit them to Gardens under which rivers flow (Paradise), abiding therein forever. Therein they shall have Azwajun Mutahharatun (purified mates or wives), and We shall admit them to shades wide and ever deepening (Paradise) .

(22) There is no good in most of their secret talks save (in) him who orders Sadaqah (charity in Allah's Cause), or Ma'ruf (Islamic monotheism and all the good and righteous deeds which Allah has ordained), or conciliation between mankind; and he who does this, seeking the good Pleasure of Allah, We shall give him a great reward.

(23) But those who believe (in the Oneness of Allah - Islamic monotheism) and do deeds of righteousness, We shall admit them to the Gardens under which rivers flow (i.e. in Paradise) to dwell therein forever. Allah's Promise is the Truth; and whose words can be truer than those of Allah? (Of course, none).

(24) And who can be better in religion than one who submits his face (himself) to Allah (i.e. follows Allah's religion of Islamic monotheism); and he is a Muhsin (a good-doer - See V.2:112). And follows the religion of Ibrahim (Abraham) Hanifa (Islamic monotheism - to worship none but Allah Alone). And Allah did take Ibrahim (Abraham) as a Khalil (an intimate friend)!

(25) Verily, those who disbelieve [by concealing the truth about Prophet Muhammad صلى الله عليه وسلم and his message of true Islamic monotheism written in the Taurat (Torah) and the Injeel (Gospel) with them] and prevent (mankind) from the Path of Allah (Islamic monotheism); they have certainly strayed far away. (Tafsir Al-Qurtubi).

(26) Verily, those who disbelieve and did wrong [by concealing the truth about Prophet Muhammad صلى الله عليه وسلم and his message of true Islamic monotheism written in the Taurat (Torah) and the Injeel (Gospel) with them]; Allah will not forgive them, nor will He guide them to any way - (Tafsir Al-Qurtubi).

(27) So, as for those who believed (in the Oneness of Allah - Islamic monotheism) and did deeds of righteousness, He will give them their (due) rewards - and more out of His Bounty. But as for those who refused His worship and were proud, He will punish them with a painful torment. And they will not find for themselves besides Allah any protector or helper.

(28) Allah has promised those who believe (in the Oneness of Allah - Islamic monotheism) and do deeds of righteousness, that for them there is forgiveness and a great reward (i.e. Paradise).

(29) Wherewith Allah guides all those who seek His Good Pleasure to ways of peace, and He brings them out of darkness by His Will unto light and guides them to the Straight Way (Islamic monotheism).

(30) "And why should we not believe in Allah and in that which has come to us of the truth (Islamic monotheism)? And we wish that our Lord will admit us (in Paradise on the Day of Resurrection) along with the righteous people (Prophet Muhammad صلى الله عليه وسلم and his Companions رضي الله عنهم)."