The religion of Islām may be broadly divided into two parts — the theoretical, or, what may be called, its articles of faith or its doctrines, and the practical, which includes all that a Muslim is required to do, that is to say, the practical course to which he must conform his life. The former are called uṣūl (plural of aṣl, meaning a root or a principle), and the latter furū‘ (plural of far‘, which means a branch). The former are also called ‘aqā’id (pl. of ‘aqīdah, lit., what one is bound to) or beliefs, and the latter aḥkām (pl. of ḥukm, lit., an order) or the ordinances and regulations of Islām. According to Shahrastāni, the former is ma‘rifah or knowledge, and the latter tā‘ah or obedience. Thus knowledge is the root; and obedience or practice, the branch. In the Holy Qur’ān the two broad divisions are repeatedly referred to as īmān1 (faith or belief) and ‘amal (deed or action) and the two words are often used together to describe a believer; those who believe and do good is the oft recurring description of true believers. The relation of faith with deeds must be constantly borne in mind in order to understand the true meaning of Islām.
The word īmān , generally translated as faith or belief, is used in two different senses in the Holy Qur’ān. According to Rāghib, the famous lexicologist of the Holy Qur’ān, īmān is sometimes nothing more than a confession with the tongue that one believes in Muḥammad, as for example in these verses: “Those who believe (āmanū) and those who are Jews, and the Christians, and the Sabians, whoever believes in Allāh and the Last Day and does good, they have their reward with their Lord … ” (2:62); “O you who believe (āmanū)! Believe in Allāh and His Messenger and the Book which He has revealed to His messenger” (4:136). But, as Rāghib has further explained, īmān also implies the condition in which a confession with the tongue is accompanied by an
1 The word īmān is, however, also used in either of the two latter senses, meaning simply the assent of the heart or the doing of good deeds. Examples of this are: “The dwellers of the desert say: We believe (āmanna). Say: You believe not, but say, We submit; and faith has not yet entered into your hearts” (49:14). Here belief clearly stands for the assent of the heart as explained in the verse itself. Or, “What reason have you that you believe not in Allāh? And the Messenger invites you that you may believe in your Lord and He has indeed made a covenant with you if you are believers” (57:8), where “believe in Allāh” means make sacrifices in the cause of truth, as the context shows. Thus the word īmān , as used in the Holy Qur’ān, signifies either simply a confession of the truth with the tongue, or simply an assent of the heart and a firm conviction of the truth brought by the Holy Prophet, or the doing of good deeds and carrying into practice of the principle accepted, or it may signify a combination of the three. Generally, however, it is employed to indicate an assent of the heart, combined, of course, with a confession with the tongue, to what the prophets bring from God, as distinguished from the doing of good deeds, and hence it is that the righteous, as already remarked, are spoken of as those who believe and do good.