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

(241) O Prophet! Strive hard against the Unbelievers and the Hypocrites, and be firm against them. Their abode is Hell,- an evil refuge (indeed).

(242) Allah sets forth, for an example to the Unbelievers, the wife of Noah and the wife of Lut: they were (respectively) under two of our righteous servants, but they were false to their (husbands), and they profited nothing before Allah on their account, but were told: "Enter ye the Fire along with (others) that enter!"

(243) Nay, who is there that can help you, (even as) an army, besides (Allah) Most Merciful? In nothing but delusion are the Unbelievers.

(244) At length, when they see it close at hand, grieved will be the faces of the Unbelievers, and it will be said (to them): "This is (the promise fulfilled), which ye were calling for!"

(245) Say: "See ye?- If Allah were to destroy me, and those with me, or if He bestows His Mercy on us,- yet who can deliver the Unbelievers from a grievous Penalty?"

(246) And the Unbelievers would almost trip thee up with their eyes when they hear the Message; and they say: "Surely he is possessed!"

(247) But truly (Revelation) is a cause of sorrow for the Unbelievers.

(248) The Unbelievers, the which there is none to ward off,-

(249) Now what is the matter with the Unbelievers that they rush madly before thee-

(250) And Noah, said: "O my Lord! Leave not of the Unbelievers, a single one on earth!