The word(s) "believer" appears 309 time(s) in 259 verse(s) in Quran in Abdullah Yusuf Ali translation.

(131) Let no man guilty of adultery or fornication marry and but a woman similarly guilty, or an Unbeliever: nor let any but such a man or an Unbeliever marry such a woman: to the believers such a thing is forbidden.

(132) Why did not the believers - men and women - when ye heard of the affair,- put the best construction on it in their own minds and say, "This (charge) is an obvious lie"?

(133) Allah doth admonish you, that ye may never repeat such (conduct), if ye are (true) believers.

(134) Those who love (to see) scandal published broadcast among the believers, will have a grievous Penalty in this life and in the Hereafter: Allah knows, and ye know not.

(135) And say to the believing women that they should lower their gaze and guard their modesty; that they should not display their beauty and ornaments except what (must ordinarily) appear thereof; that they should draw their veils over their bosoms and not display their beauty except to their husbands, their fathers, their husband's fathers, their sons, their husbands' sons, their brothers or their brothers' sons, or their sisters' sons, or their women, or the slaves whom their right hands possess, or male servants free of physical needs, or small children who have no sense of the shame of sex; and that they should not strike their feet in order to draw attention to their hidden ornaments. And O ye believers! turn ye all together towards Allah, that ye may attain Bliss.

(136) But the Unbelievers,- their deeds are like a mirage in sandy deserts, which the man parched with thirst mistakes for water; until when he comes up to it, he finds it to be nothing: But he finds Allah (ever) with him, and Allah will pay him his account: and Allah is swift in taking account.

(137) Or (the Unbelievers' state) is like the depths of darkness in a vast deep ocean, overwhelmed with billow topped by billow, topped by (dark) clouds: depths of darkness, one above another: if a man stretches out his hands, he can hardly see it! for any to whom Allah giveth not light, there is no light!

(138) They say, "We believe in Allah and in the messenger, and we obey": but even after that, some of them turn away: they are not (really) believers.

(139) The answer of the believers, when summoned to Allah and His Messenger, in order that He may judge between them, is no other than this: they say, "We hear and we obey": it is such as these that will attain felicity.

(140) Never think thou that the Unbelievers are going to frustrate (Allah's Plan) on earth: their abode is the Fire,- and it is indeed an evil refuge!