Belief is mentioned in the Quran in these verses:

[2:88] Some would say, “Our minds are made up!” Instead, it is a curse from God, as a consequence of their disbelief, that keeps them from believing, except for a few of them.

[2:93] We made a covenant with you, as we raised Mount Sinai above you, saying, “You shall uphold the commandments we have given you, strongly, and listen.” They said, “We hear, but we disobey.” Their hearts became filled with adoration for the calf, due to their disbelief. Say, “Miserable indeed is what your faith dictates upon you, if you do have any faith.”

[2:108] Do you wish to demand of your messenger what was demanded of Moses in the past? Anyone who chooses disbelief, instead of belief, has truly strayed off the right path.

[2:109] Many followers of the scripture would rather see you revert to disbelief, now that you have believed. This is due to jealousy on their part, after the truth has become evident to them. You shall pardon them, and leave them alone, until God issues His judgment. God is Omnipotent.

[3:52] When Jesus sensed their disbelief, he said, “Who are my supporters towards God?” The disciples said, “We are God’s supporters; we believe in God, and bear witness that we are submitters.”

[3:90] Those who disbelieve after believing, then plunge deeper into disbelief, their repentance will not be accepted from them; they are the real strayers.

[3:106] The day will come when some faces will be brightened (with joy), while other faces will be darkened (with misery). As for those whose faces are darkened, they will be asked, “Did you not disbelieve after believing? Therefore, suffer the retribution for your disbelief.”

[3:167] And to expose the hypocrites who were told, “Come fight in the cause of God, or contribute.” They said, “If we knew how to fight, we would have joined you.” They were closer to disbelief then than they were to belief. They uttered with their mouths what was not in their hearts. God knows what they conceal.

[3:177] Those who choose disbelief, instead of belief, do not hurt God in the least; they have incurred a painful retribution.

[4:25] Those among you who cannot afford to marry free believing women, may marry believing slave women. God knows best about your belief, and you are equal to one another, as far as belief is concerned. You shall obtain permission from their guardians before you marry them, and pay them their due dowry equitably. They shall maintain moral behavior, by not committing adultery, or having secret lovers. Once they are freed through marriage, if they commit adultery, their punishment shall be half of that for the free women. Marrying a slave shall be a last resort for those unable to wait. To be patient is better for you. God is Forgiver, Most Merciful.

[4:46] Among those who are Jewish, some distort the words beyond the truth, and they say, “We hear, but we disobey,” and “Your words are falling on deaf ears,” and “Raa’ena (be our shepherd),” as they twist their tongues to mock the religion. Had they said, “We hear, and we obey,” and “We hear you,” and “Unzurna (watch over us),” it would have been better for them, and more righteous. Instead, they have incurred condemnation from God due to their disbelief. Consequently, the majority of them cannot believe.

[4:137] Surely, those who believe, then disbelieve, then believe, then disbelieve, then plunge deeper into disbelief, God will not forgive them, nor will He guide them in any way.

[4:155] (They incurred condemnation) for violating their covenant, rejecting God’s revelations, killing the prophets unjustly, and for saying, “Our minds are made up!” In fact, God is the One who sealed their minds, due to their disbelief, and this is why they fail to believe, except rarely.

[5:61] When they come to you, they say, “We believe,” even though they were full of disbelief when they entered, and they are full of disbelief when they leave. God is fully aware of everything they conceal.

[5:64] The Jews even said, “God’s hand is tied down!” It is their hands that are tied down. They are condemned for uttering such a blasphemy. Instead, His hands are wide open, spending as He wills. For certain, your Lord’s revelations to you will cause many of them to plunge deeper into transgression and disbelief. Consequently, we have committed them to animosity and hatred among themselves until the Day of Resurrection. Whenever they ignite the flames of war, God puts them out. They roam the earth wickedly, and God dislikes the evildoers.

[5:68] Say, “O people of the scripture, you have no basis until you uphold the Torah, and the Gospel, and what is sent down to you herein from your Lord.” For sure, these revelations from your Lord will cause many of them to plunge deeper into transgression and disbelief. Therefore, do not feel sorry for the disbelieving people.

[6:30] If you could only see them when they stand before their Lord! He would say, “Is this not the truth?” They would say, “Yes, by our Lord.” He would say, “You have incurred the retribution by your disbelief.”

[6:70] You shall disregard those who take their religion in vain, as if it is a social function, and are totally absorbed in this worldly life. Remind with this (Quran), lest a soul may suffer the consequences of its evil earnings. It has none beside God as a Lord and Master, nor an intercessor. If it could offer any kind of ransom, it would not be accepted. They suffer the consequences of the evil works they earn; they have incurred hellish drinks, and a painful retribution because of their disbelief.

[6:82] Those who believe, and do not pollute their belief with idol worship, have deserved the perfect security, and they are truly guided.

[6:158] Are they waiting for the angels to come to them, or your Lord, or some physical manifestations of your Lord? The day this happens, no soul will benefit from believing if it did not believe before that, and did not reap the benefits of belief by leading a righteous life. Say, “Keep on waiting; we too are waiting.”

[8:35] Their Contact Prayers (Salat) at the shrine (Ka`bah) were no more than a mockery and a means of repelling the people (by crowding them out). Therefore, suffer the retribution for your disbelief.

[9:17] The idol worshipers are not to frequent the masjids of God, while confessing their disbelief. These have nullified their works, and they will abide forever in Hell.

[9:37] Altering the Sacred Months is a sign of excessive disbelief; it augments the straying of those who have disbelieved. They alternate the Sacred Months and the regular months, while preserving the number of months consecrated by God. They thus violate what God has consecrated. Their evil works are adorned in their eyes. God does not guide the disbelieving people.

[9:74] They swear by God that they never said it, although they have uttered the word of disbelief; they have disbelieved after becoming submitters. In fact, they gave up what they never had. They have rebelled even though God and His messenger have showered them with His grace and provisions. If they repent, it would be best for them. But if they turn away, God will commit them to painful retribution in this life and in the Hereafter. They will find no one on earth to be their lord and master.

[9:97] The Arabs are the worst in disbelief and hypocrisy, and the most likely to ignore the laws that God has revealed to His messenger. God is Omniscient, Most Wise.

[10:9] As for those who believe and lead a righteous life, their Lord guides them, by virtue of their belief. Rivers will flow beneath them in the gardens of bliss.

[16:106] Those who disbelieve in God, after having acquired faith, and become fully content with disbelief, have incurred wrath from God. The only ones to be excused are those who are forced to profess disbelief, while their hearts are full of faith.

[17:69] Have you guaranteed that He will not return you to the sea another time, then send upon you a storm that drowns you because of your disbelief? Once this happens, we will not give you another chance.

[17:84] Say, “Everyone works in accordance with his belief, and your Lord knows best which ones are guided in the right path.”

[18:80] “As for the boy, his parents were good believers, and we saw that he was going to burden them with his transgression and disbelief.

[18:106] Their just requital is Hell, in return for their disbelief, and for mocking My revelations and My messengers.

[31:23] As for those who disbelieve, do not be saddened by their disbelief. To us is their ultimate return, then we will inform them of everything they had done. God is fully aware of the innermost thoughts.

[34:17] We thus requited them for their disbelief. Do we not requite only the disbelievers?

[35:39] He is the One who made you inheritors of the earth. Subsequently, whoever chooses to disbelieve does so to his own detriment. The disbelief of the disbelievers only augments their Lord’s abhorrence towards them. The disbelief of the disbelievers plunges them deeper into loss.

[36:8] For we place around their necks shackles, up to their chins. Consequently, they become locked in their disbelief.

[36:64] Today you will burn in it, as a consequence of your disbelief.

[39:8] When the human being is afflicted, he implores his Lord, sincerely devoted to Him. But as soon as He blesses him, he forgets his previous imploring, sets up idols to rank with God and to divert others from His path. Say, “Enjoy your disbelief temporarily; you have incurred the hellfire.”

[40:28] A believing man among Pharaoh’s people, who was concealing his belief, said, “How can you kill a man just for saying, `My Lord is God,’ and he has shown you clear proofs from your Lord? If he is a liar, that is his problem, and if he is truthful, you benefit from his promises. Surely, God does not guide any transgressor, liar.

[40:85] Their belief then could not help them in the least, once they saw our retribution. Such is God’s system that has been established to deal with His creatures; the disbelievers are always doomed.

[46:34] The day the disbelievers are introduced to the Hellfire, they will be asked, “Is this not the truth?” They will answer, “Yes indeed, by our Lord.” He will say, “Then suffer the retribution for your disbelief.”

[49:7] And know that God’s messenger has come in your midst. Had he listened to you in many things, you would have made things difficult for yourselves. But God made you love faith and adorned it in your hearts, and He made you abhor disbelief, wickedness, and disobedience. These are the guided ones.

[49:14] The Arabs said, “We are Mu’mens (believers).” Say, “You have not believed; what you should say is, `We are Muslims (submitters),’ until belief is established in your hearts.” If you obey God and His messenger, He will not put any of your works to waste. God is Forgiver, Most Merciful.

[52:21] For those who believed, and their children also followed them in belief, we will have their children join them. We never fail to reward them for any work. Every person is paid for what he did.

[59:11] Have you noted those who are plagued with hypocrisy, and how they said to their companions in disbelief among the people of the scripture, “If you are evicted we will go out with you, and will never obey anyone who opposes you. If anyone fights you, we will fight on your side.” God bears witness that they are liars.

[60:10] O you who believe, when believing women (abandon the enemy and) ask for asylum with you, you shall test them. God is fully aware of their belief. Once you establish that they are believers, you shall not return them to the disbelievers. They are not lawful to remain married to them, nor shall the disbelievers be allowed to marry them. Give back the dowries that the disbelievers have paid. You commit no error by marrying them, so long as you pay them their due dowries. Do not keep disbelieving wives (if they wish to join the enemy). You may ask them for the dowry you had paid, and they may ask for what they paid. This is God’s rule; He rules among you. God is Omniscient, Most Wise.

[60:13] O you who believe, do not befriend people with whom God is angry, and who are hopelessly stuck in disbelief; they are just as hopeless as the disbelievers who are already in the graves.

[91:11] Thamoud’s disbelief caused them to transgress.

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