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

(31) But those among them who are well-grounded in knowledge, and the believers, believe in what hath been revealed to thee and what was revealed before thee: And (especially) those who establish regular prayer and practise regular charity and believe in Allah and in the Last Day: To them shall We soon give a great reward.

(32) This day are (all) things good and pure made lawful unto you. The food of the People of the Book is lawful unto you and yours is lawful unto them. (Lawful unto you in marriage) are (not only) chaste women who are believers, but chaste women among the People of the Book, revealed before your time,- when ye give them their due dowers, and desire chastity, not lewdness, nor secret intrigues if any one rejects faith, fruitless is his work, and in the Hereafter he will be in the ranks of those who have lost (all spiritual good).

(33) O ye who believe! Call in remembrance the favour of Allah unto you when certain men formed the design to stretch out their hands against you, but (Allah) held back their hands from you: so fear Allah. And on Allah let believers put (all) their trust.

(34) It was We who revealed the law (to Moses): therein was guidance and light. By its standard have been judged the Jews, by the prophets who bowed (as in Islam) to Allah's will, by the rabbis and the doctors of law: for to them was entrusted the protection of Allah's book, and they were witnesses thereto: therefore fear not men, but fear me, and sell not my signs for a miserable price. If any do fail to judge by (the light of) what Allah hath revealed, they are (no better than) Unbelievers.

(35) O ye who believe! if any from among you turn back from his Faith, soon will Allah produce a people whom He will love as they will love Him,- lowly with the believers, mighty against the rejecters, fighting in the way of Allah, and never afraid of the reproaches of such as find fault. That is the grace of Allah, which He will bestow on whom He pleaseth. And Allah encompasseth all, and He knoweth all things.

(36) Your (real) friends are (no less than) Allah, His Messenger, and the (fellowship of) believers,- those who establish regular prayers and regular charity, and they bow down humbly (in worship).

(37) As to those who turn (for friendship) to Allah, His Messenger, and the (fellowship of) believers,- it is the fellowship of Allah that must certainly triumph.

(38) Thou seest many of them turning in friendship to the Unbelievers. Evil indeed are (the works) which their souls have sent forward before them (with the result), that Allah's wrath is on them, and in torment will they abide.

(39) Strongest among men in enmity to the believers wilt thou find the Jews and Pagans; and nearest among them in love to the believers wilt thou find those who say, "We are Christians": because amongst these are men devoted to learning and men who have renounced the world, and they are not arrogant.

(40) Then will Allah say: "O Jesus the son of Mary! Recount My favour to thee and to thy mother. Behold! I strengthened thee with the holy spirit, so that thou didst speak to the people in childhood and in maturity. Behold! I taught thee the Book and Wisdom, the Law and the Gospel and behold! thou makest out of clay, as it were, the figure of a bird, by My leave, and thou breathest into it and it becometh a bird by My leave, and thou healest those born blind, and the lepers, by My leave. And behold! thou bringest forth the dead by My leave. And behold! I did restrain the Children of Israel from (violence to) thee when thou didst show them the clear Signs, and the unbelievers among them said: 'This is nothing but evident magic.'