Question: Does iman increase or decrease?
ANSWER
Hadrat Imam-i Rabbani states:
Since iman is heart’s confirmation and knowledge, it does not increase or decrease. A belief that increases or decreases is not considered iman, but supposition. By performing acts of worship and deeds liked by Allahu ta’ala, iman is polished, shines, and brightens. When a prohibited act is committed, iman gets cloudy. Then a change occurs in the luster of iman on account of deeds. It does not happen in itself. Some (scholars) said that the iman which is bright is very much greater than that which is not bright. They almost did not consider some beliefs that are not bright as iman. And about some lustrous ones they said that they were iman but that they were small. This case with iman is like the case of two mirrors standing opposite each other with different brightness. It is similar to saying that the one which is more lustrous and reflects the things opposite itself more brightly is greater than the one that reflects less brightly. And another person, for example, says that the two mirrors are equal. They are different only in brightness, in reflecting the things opposite themselves; that is, their properties, qualities are different. The former has looked at the appearance and has not penetrated into the essence. It is stated in a hadith-i sharif, “The iman of Abu Bakr is heavier than the total sum of the imans of my Ummah.” And this is in regard to the luster of iman. (Maktubat, Letter 266)

Iman does not increase or decrease
Question: For some people, it is said, “His iman is much.” Does iman increase, proliferate, or decrease?
ANSWER
Iman means to believe the facts coming from our Prophet, which are written in the books of Ahl as-Sunnat scholars, and to express one’s belief. It is written in the book Durr-i Yakta that it is permissible to express one’s belief in any language. Acts of worship are not from iman, but they perfect and beautify iman. Hadrat Imam-i A’zam Abu Hanifa said that iman does not increase or decrease because it means the heart’s admitting and believing. There is no scarcity or abundance in iman. Belief which has its decrease or increase is not called iman, but supposition or illusion. Iman’s being much or little means muchness or scarcity in acts of worship. When a person increases their acts of worship, they are said to have much perfection in their iman. The imans of Believers are unlike the imans of prophets because prophets’ iman has reached the summit of perfection on account of acts of worship. The iman of other Believers cannot reach there, but both have the common quality of being iman. The former has become different through acts of worship. It is as if there were no resemblance between them. All Believers and prophets share the property of being human. But other values, superiorities have made prophets reach higher grades.

Iman does not decrease, increase, or proliferate
Question: There are people who say, “Deeds and acts of worship are from iman. One who does not do acts of worship loses iman. Moreover, iman decreases and increases.” Is it right?
ANSWER
It is of iman to believe that acts of worship are a duty. Believing and performing are two different concepts that should not be confused with each other. Anyone who, though they have believed but because they are lazy, does not perform acts of worship does not become a disbeliever. The forty-third verse of the famous book Qasidat al-Amali says: “The fard ibadat are not included in iman.” Iman means belief. There is neither paucity nor plentifulness in believing. If acts of worship were of iman, iman would increase or decrease. The belief will not be accepted after the curtain rises up from in front of the eyes and the torture is seen [at the moment one dies]. Those who pass away with iman at that moment, when acts of worship cannot be performed, believe only by the heart. This is called iman in the Qur’anic verse. In many verses, those who have iman are ordered to perform acts of worship. Therefore, belief is separate from acts of worship. Furthermore, the Qur’anic phrase “Those who believe and those who do pious deeds” shows that acts of worship and iman are distinct. The verse “Those who, being Believers, do pious deeds” shows clearly that deeds are separate from belief. It was stated unanimously that anyone, just after becoming a Believer, died and found no time to perform any act of worship was a Believer. It is declared in the Hadith al-Jibril that iman is only belief.

Does iman increase or decrease?
Question: Iman is to accept and believe in specific things. Can it decrease or increase?
ANSWER
The revelation with the tongue of the iman in the heart is necessary for the reason that it will help Muslims to recognize one another. The Muslim who does not say they are a Believer is a Believer, too. Deeds and acts of worship are not included in iman. Most scholars, for example, Hadrat Imam-i A’zam Abu Hanifa, said so. Though Hadrat Ali and Imam Shafi’i said that iman was to believe and to confirm it with the tongue and to perform acts of worship, they, in fact, meant the perfection and maturity of iman. It was a unanimous declaration that the one who said that one had iman in one’s heart was a Believer. Imam-i Muhyiddin Nawawi states:

“Iman increases by studying and understanding the reasons of the facts to be believed. Hadrat Abu Bakr’s iman is not the same as the iman of any other person.” This statement points to the strength or weakness of iman; it does not mean that iman itself increases or decreases. It is likened to the similarity between sick and healthy persons. They are not equally strong, but both are human beings, and their being human neither increases nor decreases. Hadrat Imam-i A’zam explained the verses and hadiths about the attributes of iman as follows:

“Blessed Companions, when they embraced Islam, believed everything as a whole. Later many new things became fard in the course of time. They believed these orders one by one. Thus their belief increased gradually. This is true only for Blessed Companions. The increase of iman cannot be thought of for Muslims who came after them.”

Acts of worship make iman mature and beautiful and are like the branches of a tree. Iman neither increases by worshiping nor decreases by sinning because iman means thorough belief and therefore neither increases nor decreases. The increase of iman in the heart means the decrease of kufr, the opposite of belief, which is impossible. Imam Shafi’i and Imam Abul Hasan Ash’ari said that iman would increase or decrease.  But it is explained in the book Mawaqif that they meant with this statement the increase or decrease of not iman, but the strength of iman. In his book Fiqh-i Akbar, Hadrat Imam A’zam states:

“The iman of the ones in the heavens and on the earth does not become less or more in respect to the facts to be believed, but in respect to itminan and yaqin. In other words, the strength of iman increases or decreases. But without any yaqin and strength, it is not iman,

Note: For detailed information, see the article Is every sinner a disbeliever