by Ustadh Luqman al-Andalusi
Kafir (Arabic: كافر kāfir; plural كفّار kuffār) is a term used in Islamic doctrine, usually translated as “unbeliever” or “disbeliever” or sometimes “infidel.” The term refers to a person who rejects God or who hides, denies, or “covers” the truth.
An example of a famous scholar being called Kafir
 Imam Ibn ‘Abidin (rh) said that this happened to Abd al-Wahhab as-Sha‘rani, against whom envious people forged calumnies of kufr by inserting into some of his works (which they published as his). Whereupon the Ulema (scholars) of the day met, and he produced his own copy of the book which had been signed by scholars [and proved to be free of the lies forged against him]. (Radd al-Muhtar)
Worrying about one’s own state of Iman (faith)
 “We believe in Allah, and that which has been sent down to us” (Qur’an, 2:136).
 Abu Hamid Al-Ghazalli (rh) said: “You may ask, ‘What then have the good, early generation meant with the saying: ‘Allah willing, I am a believer!'” A qualification implies doubt, and to entertain doubts concerning the veracity of belief amounts to unbelief. Yet allof the early generation used to refrain from giving a definite reply concerning belief, and were extremely careful not to commit themselves.
When Sufyan ath-Thawri (rh) made this statement he was asked, “What then shall we say?” Thereupon he replied, “We believe in Allah, and that which has been sent down to us” (Qur’an, 2:136).
 Sufyan Ath-Thawri (rh) said, “We believe in Allah and in His Angels, Books, and Prophets. But we do not know what we are before Allah.” You may ask all this and say, “What then is the meaning of all these qualifications?”
The answer to your question is that these qualifications are correct and are put forward for four reasons, two of which arise from doubt (not of the reality of belief itself but of its end and perfection); and two do not arise from doubt at all.”
 And what is the difference between saying “We believe in Allah and that which has been sent down to us” and saying, “I am a believer?”
Once al-Hasan al-Basri (rh) was asked, “Are you a believer?” to which he replied, “If it is the Will of Allah.” Thereupon he was told, “O Abu-Sa’id? Why do you qualify your belief?” He answered and said, “I fear saying, ‘Yes’, and then Allah will say, `You have lied Hasan.’ Then I shall rightly merit His punishment.” He also used to say, “I fear that Allah may find that I have done something abominable to Him and He will consequently abhor me and say, ‘Go away. I accept none of your deeds.’ Then I shall be working in vain.”
 Ibrahim ibn Adham (rh) once said: “Whenever you are asked, `Are you a believer?’ say,
‘La Ilaha Illa Allah (There is no deity worthy of worship except Allah).'” At another time he said, “Say, ‘I do not doubt belief; your question to me is a (bid`a) innovation.'”
 The great scholar Alqamah (rh) was once asked, “Are you a believer?” to which he replied, “I hope so, Allah willing.”
 Ali ibn Abi Talib (ra) said, “Indeed belief will loom as a single white spot in the heart of man. If the man will do that which is good the white spot will grow and spread until the whole heart is white. Whereas hypocrisy makes it first appearance as a black blotch in the heart of a man. If the man will do that which is unlawful, the black blotch will grow and spread until the whole heart is black, and blackness becomes man’s second nature.” Allah says: “No, but what they used to do has veiled their hearts” (Qur’an 83:14).
The Sunnah is to fear hypocrisy and unbelief in oneself, not others.
 Ali Ibn Abi Talib (ra) said, “He is the wisest and the most knowing man who advises people not to lose hope and faith in the Mercy of Allah and not to be too sure and over-confident of immunity from His Wrath and Punishment.”
 Abu Sa’id al-Khudri (ra) said, “The hearts are of four kinds: a sealed heart, which is the heart of the unbeliever; a two-faced heart, which is the heart of the hypocrite; a clean heart from the midst of which a radiant lamp sheds its radiant light; and a heart which contains some belief and some hypocrisy. The belief it contains is like a vegetable which receives its nourishment from fresh waters. The hypocrisy it contains is like an ulcer which feeds on pus and blood; whichever of the two substances that prevails will determine its fate.” According to another narration, “Whichever will prevail will seal his doom.” The Prophet ﷺ also said, “The most hypocritical people of this nation are those among the reciters (of the Qur’an).” In another narration he said, “Polytheism among my people is more subtle than the creeping of an ant on a rock.”
 Hudhayfah (ra) said, “During the time of the Prophet ﷺ there were things which made the man who repeated them a hypocrite as long as he lived. However, now, I hear these same things repeated ten times a day (and no one seems to mind).” A learned man said, “The person closest to hypocrisy is he who deems himself free thereof.”
 Hudhayfah (ra) also said, “Hypocrites are more numerous today than they were at the time of the Prophet ﷺ. At that time they used to conceal their hypocrisy; now they reveal it.” Such hypocrisy militates against the reality of belief as well as against its perfectness. It is something concealed and subtle; the farthest removed from it are those who are constantly afraid of it, while those who deem themselves free of it are they who are nearest to it.
 Al Hasan al Basri (rh) was once told, “There is no more hypocrisy nowadays.” To which he replied, “Brother! Were the hypocrites to perish from the land you would feel lonely on the way.” Again either Al Hasan himself or someone else said, “Were tails to grow on the backs of the hypocrites and trail behind them our feet would no longer be able to touch the earth.”
 Ibn `Umar (ra) on hearing a man speak disparagingly of al Hajjaj (the Umayyad governor), told him, “Would you speak disparagingly of him if he were here present?” The man answered, “No.” Thereupon Ibn `Umar said, “We used to consider this hypocritical at the time of the Prophet ﷺ. The Prophet ﷺ said, `He who has a fork-tongue in this world will, in the Hereafter, be made fork-tongued by Allah'”.
 Al Hasan al-Basri (rh) was once told, “There are some who say that they do not fear hypocrisy.” Thereupon he answered, “By Allah, I would rather be sure that I am free of hypocrisy than have all the gold in the world.”
Al Hasan also said, “Among the different kinds of hypocrisy are the disagreements between the tongue and the heart, between the concealed and the revealed, and between the entrance and the exit.”
 Ibn abi Mulaykah (rh) said, “I have known one hundred and thirty of the Companions of the Prophet ﷺ, all of whom feared hypocrisy.”
 Sari as-Saqti (rh) once said, “If a person enters a garden containing trees of every kind and on them are birds of every kind, and then each bird calls to him in a different language saying, `Peace be upon you, O friend of Allah’, and as a result he feels very well pleased and satisfied, he becomes their captive.”