Usul al-Kafi
Book 5:
The Book of Belief and Disbelief

Chapter 20
Grades of belief

643. 1. Imam Jafar as-Sadiq (p): God, the Almighty, the Glorious, has classified faith (Iman) into seven attributes: kindness, truthfulness, conviction (Yaqin), acceptance of God’s Will, loyalty, knowledge (Ilm) and modesty. God, the Almighty, distributed it among the people. The one in whom all these seven attributes are found is perfect and capable of withstanding. Some possess only one attribute, some others two, still others three, till it reaches seven. Do not put the pressure of two attributes on one who has only one attribute and the pressure of three attributes on one who has only two attributes, and so on.(B5,C20,T1)