Iman or faith has been linguistically defined as believing and confidence. Termly, it is defined as the expression of the tongue, the conviction of the heart and the work of the organs, and it increases and decreases. The expression of the tongue refers to the declaration of faith; that is no one is worthy of worship except Allah, and Muhammad is Allah’s Messenger. The conviction of the heart is to believe in Allah, His Angels, His Books, His Prophets, the Last Day and the Divine Decree. The work of the organs means the observance of good deeds and the abstention from misdeeds. This is the position of Ahl Al-Sunnah Wal-Jama`ah (the followers of Sunnah and Muslim community) regarding the concept of Iman.
Ibn Taymiyyah mentioned in his book Al-Fatwa that Imam Al-Shafi`i said, “There has been an Ijma` (unanimous agreement) among the companions of the Prophet, their followers and our scholars that Iman (faith) is a declaration, work and conviction and that none of the three suffices for the others.”
Ahl Al-Sunnah view that Iman can be increased or decreased; it increases by doing good deeds, acts of worship and contemplating on the Qur’an, rulings of Islam, hadiths and the creation of Allah, and decreases by misdeeds, following evil desires and Satan and negligence of reciting the Qur’an.
Narrated Abu Hurairah: “The Prophet (peace be upon him) said, “Iman consists of more than sixty branches, and modesty is a branch of faith.” (Al-Bukhari)
This meaningful and highly expressive narration is one of the greatest hadiths of Islam. It deals with the concept of Iman and highlights one of its parts, namely modesty’. The Prophet (peace be upon him) shows us that the term of Iman is not restricted to mere believing. Yet, it includes actions as well. He informs us that Iman consists of more than sixty parts and it includes sayings and deeds, as mentioned in other narrations of the hadith.
Yet, someone may say, “The Prophet was asked ‘what is Iman?’ in the well-known hadith of Jibril (angel Gabriel) and he restricted the meaning of Iman to beliefs.” Sheikh Ibn `Uthaimin clarifies this by saying, “Iman in the sense of belief is based on six principles, which are mentioned in the hadith of Jibril (peace be upon him), when he questioned the Prophet (peace be upon him), who said: “Iman means to believe in Allah, His Angels, His Books, His Messengers, the Last Day, and the Divine Decree, both good and bad.” (Al-Bukhari and Muslim)
Yet, the broad meaning of Iman includes good deeds of various kinds and it has seventy-odd branches. In this context, Allah called prayer Iman in His Saying:
And never would Allah have caused you to lose your Iman. Indeed Allah is, to the people, Kind and Merciful. (Al-Baqarah 2:143)
The scholars of Tafsir (Qur’an Exegesis) said: “Iman” here means prayer, because the companions used to pray towards Al-Masjid Al-Aqsa before they were commanded to face the Ka`bah in their prayers.”
The hadith at hand confirms the stance of Ahl Al-Sunnah, that is Iman is not only restricted to beliefs but it includes deeds. In the hadith, the Prophet mentions that modesty’, which is the work of organs, is a branch or part of faith. Also, there is another narration of the hadith reported by Muslim on the authority of Abu Hurairah that the Prophet (peace be upon him) said, “Iman has sixty odd or seventy odd branches. The uppermost of all these is the Testimony of Faith “La ilaha illallah” (there is no true god except Allah) while the least of them is the removal of the harmful objects from the road. And modesty’ is a branch of Iman.” Thus, it considered the declaration of faith and the work of organs, represented in the removal of harmful objects from the road and modesty’, as branches and parts of Iman.
Actually, this is an extremely important principle that should be understood and taken into consideration. There are those who claim that pronouncing the Testimony of Faith is enough to be a believer deserving the Mercy of Allah and His Paradise. This hadith refutes these false claims, because a Muslim has to work hard to get closer to Allah by means of acts of worship.
A Muslim with perfect faith is the one who declares Islam by the tongue, believes in Allah, His Messenger and what they told, and performs the good deeds and refrains from misdeeds. Those who declare Islam without observing the good deeds and refraining from misdeeds are with weak Iman and are treading the ways of Satan to the hellfire.
In the same context, there are some sects that went to the extremes in this matter. They deemed actions as part of Iman but they did not admit that Iman decreases or increases. Those are the Khawarij. They believe that Iman neither decreases nor increases. For them, Iman is inseparable and is lost by committing major misdeeds. Thus, they consider a Muslim who commits major sins as disbeliever or non-Muslim. Therefore, they fell in the quagmire of Takfir (considering Muslims as non-Muslims) and violated the rules of Islam. They deemed a lot of Muslims as non-Muslims because they committed some sins.
Actually, the fact that Iman increases and decreases is a separator between Ahl Al-Sunnah and misguided sects. Ahl Al-Sunnah believe that Iman (faith) increases by doing good deeds and decreases by committing wrongdoings. Ahl Al-Sunnah have a middle position, admitting that a believer who commits bad deeds, even most of the major sins, is still a believer but with weak Iman. I said, “most of major sins” because some major sins rules a Muslim out of Islam, such as cursing the Prophet, denying parts of the Qur’an and accusing Lady `A’ishah (the Prophet’s wife, may Allah be pleased with her) with adultery.
The followers of Sunnah neither exclude actions from Iman nor consider negligence or committing sins a kind of apostasy. Their position is in the middle and avoids both extremes.
In fact, ruling a believer out of Islam is contingent on certain conditions that must be met. These conditions are relevant to the sin itself, the doer and his awareness of the ruling. Ibn `Uthaimin said, “There are four prerequisites to deem a person as Kafir “disbeliever”: First, the saying or action committed or neglected must be established to be requiring the state of apostasy. Second, the doer must be established to commit it and he or she is in a state of legal accountability. Third, he or she must have known and understood the ruling of this act or negligence. Fourth, there must be no restraints of ruling the doer as an apostate.”
We should be aware of these important facts, because unfortunately, the Muslim nation has been subject to great misfortunes and calamities due to the problem of Takfir. This problem spread among Muslim youth and groups causing great losses and catastrophes. In fact, determining someone as a believer or disbeliever is not up to us. Rather, it is up to Allah and His Messenger (peace be upon him). The basic principle is that the one who appears outwardly to be a Muslim is regarded so, until it is proven otherwise based on acceptable and authentic legal proofs. Takfir (ruling others as disbelievers) is an extremely dangerous matter and one should keep away from it. The Prophet (peace be upon him) said, “If a man declares his brother to be a kafir, it will apply to one of them.” (Al-Bukhari and Muslim)
May Allah preserve the Muslim nation of all that harms it!
 The Islamic Research Magazine, vol. 17, http://www.alifta.net/Fatawa/fatawaChapters.aspx?View=Page&PageID=2495&PageNo=1&BookID=2 (last accessed 24-11-2013)
 Ibn Taymiyyah, Majmu` Al-Fatawa, King Saud Edition, 1381 AH, vol. 7, pp. 170-171.
 Ibn `Uthaimin, Fatwa Ibn `Uthaimin, vol. 1. p. 54.
 Ibn `Uthaimin, Fatwa Ibn `Uthaimin, vol. 3. Al-Wala’ and Al-Bara’ section.Soucre Link