The word(s) "believer" appears 651 time(s) in 556 verse(s) in Quran in Mohsin Khan translation.

(391) Save the chosen slaves of Allah (i.e. the true believers of Islamic Monotheism).

(392) Truly We have made it (as) a trail for the Zalimun (polytheists, disbelievers, wrong-doers).

(393) Except the chosen slaves of Allah (faithful, obedient, and true believers of Islamic Monotheism).

(394) Then We drowned the others (disbelievers and polytheists).

(395) Except the slaves of Allah, whom He chooses (for His Mercy i.e. true believers of Islamic Monotheism who do not attribute false things unto Allah).

(396) Cannot lead astray [turn away from Him (Allah) anyone of the believers],

(397) "We would have indeed been the chosen slaves of Allah (true believers of Islamic Monotheism)!"

(398) And they (Arab pagans) wonder that a warner (Prophet Muhammad صلى الله عليه وسلم) has come to them from among themselves. And the disbelievers say: "This (Prophet Muhammad صلى الله عليه وسلم) is a sorcerer, a liar.

(399) Shall We treat those who believe (in the Oneness of Allah - Islamic Monotheism) and do righteous good deeds as Mufsidun (those who associate partners in worship with Allah and commit crimes) on earth? Or shall We treat the Muttaqun (the pious - See V.2:2) as the Fujjar (criminals, disbelievers, the wicked)?

(400) This is so! And for the Taghun (transgressors, the disobedient to Allah and His Messenger - disbelievers in the Oneness of Allah, criminals) will be an evil final return (Fire).