Eemaan consists of:
Statements by the tongue. For example, the statement: Laa ilaaha illal-laah.
Deeds according to the pillars. For example, bowing in prayer.
Affirmation in the Heart. For example, belief in Allaah, His angels, etc. among the things that must be believed in.
Allaah, Most High, said: “And they were only commanded to worship Allaah, making the religion sincerely for Him Alone, to establish regular prayer and to give compulsory charity, and that is the right religion.” Soorah al-Bayyinah 98:5. Whereby He made worship of Allaah, Most High, sincerity of the heart, establishment of salaah (formal prayer), and giving zakaah all a part of the religion.
The Messenger of Allaah (S.A.W.) said: “Faith has seventy odd branches. The highest is the declaration Laa ilaaha illallaah, and its lowest is the zakaah removal of something harmful from the road.” Sahih Muslim
It increases and decrease : “And whenever a chapter is revealed, some of them say: ‘Which of you has had his faith increased by it?’ As for those who believe, it has increased their faith…” Soorah at-Tawbah 9:124
The Messenger of Allaah (S.A.W.) also said: “Whoever said Laa ilaaha illallaah, and there was in his heart faith equivalent to the weight of a grain of wheat, or a mustard seed, or an atom,he will be removed from the fire.” Sahih Al-Bukhari
Some would say that eemaan consists of knowledge and reject statements of tongue, actions of the limbs and affirmation of the heart, thus making Pharaoh and even iblees perfect believers since they knew very well about Allah.
Another group are those who restricted eemaan to the profession on the tongue without including the affirmation of the heart. Therefore, according to their view, the hypocrites are perfect believers. Nevertheless, they believe that the hypocrites will suffer the punishment that Allaah has promised them. Thus they contradict themselves.
Those who state that eemaan is belief in the heart and profession on the tongue and they remove deeds from the definition of eemaan. who said that eemaan was assent (tasdeeq) in the heart and an utterance on the tongue but does not include works, Their claims were not like those of the formers, for at least they recognized that one is not a believer if he does not express his belief verbally, though he is able to do so. They also acknowledged that Iblees, Pharaoh, and others were unbelievers despite the fact that they believed the truth in their hearts. However, if they did not include the works of the heart in their definition of belief, they would have been obliged to adopt the view of the former…These last group, especially their theologians and jurists from among them, regarded works as part of eemaan in a figurative way, for a work is the fruit and requirement of eemaan.”
A Commentary on Ibn Qudaamah al-Maqdisee’s
The Radiance of Faith
Leading to the Path of Faith
by Dr. Bilal Philips