And the Prophet—may Allah bless him and grant him peace—said:

“Faith has seventy-odd branches. The highest is saying, ‘There is no deity worthy of worship except Allah,’ and the lowest is removing something harmful from the road.”

He also said to the delegation of ‘Abd al-Qays:

“I command you to have faith in Allah. Do you know what faith in Allah is? To testify that there is no deity worthy of worship except Allah and to pay one-fifth of whatever spoils you acquire.”

The early generations unanimously agreed that faith consists of words and deeds, and that it increases and decreases. This means the affirmation and actions of the heart, followed by the speech of the tongue and the deeds of the limbs. The heart’s affirmation is firm assent to Allah, His angels, His Books, His Messengers, and the Last Day. This includes believing in everything the Messenger—may Allah bless him and grant him peace—brought.

People differ in this respect. Some affirm it as a whole without knowing its details, while others affirm it both as a whole and in detail. Some remain constantly mindful of this affirmation and keep it present in their hearts, while others become heedless of it and lose awareness of it. Some gain clear insight into it through the light and faith Allah casts into their hearts. Others are firmly convinced on the basis of evidence against which a doubt might arise, or through firm reliance on the authority of others.

This affirmation is followed by the actions of the heart: loving Allah and His Messenger; venerating Allah and His Messenger; supporting and honoring the Messenger; fearing Allah; turning to Him in repentance; being sincere to Him; relying upon Him; and other such states. All these actions of the heart are part of faith. Affirmation and conviction necessarily give rise to them, just as a cause necessarily produces its effect. Conviction is followed by the speech of the tongue, and the heart’s actions are followed by bodily deeds, such as prayer, zakah, fasting, Hajj, and the like.