Knowledge must include the heart’s affirmation and an understanding of the meaning of what one is required to know, and it is not deemed complete unless one acts according to that knowledge in every situation as the circumstances demand.

This very knowledge that Allah has commanded is an individual obligation upon every single person; no one, whoever he may be, is excused from it. The need for this knowledge and for acting upon it—as it perfects one’s devotion (taʾalluh) to Allah—surpasses every other need.

Knowing anything is contingent upon recognizing the path that leads to it and then following that path. The routes that, in a broad and general sense, lead to knowing that “there is no god but He” are several:

• The first—and it is the greatest, clearest, and strongest—is to contemplate Allah’s names, attributes, and actions, all of which point to His perfection, magnificence, and majesty. Truly understanding them necessitates the certainty that no one besides Him deserves to be worshipped, and it impels one to strive in devotion and worship of the Perfect One, to whom belong all praise, glory, majesty, and beauty.

• The second route is to realize that He alone is the Lord who creates, provides, and manages all affairs; from this it follows that He alone is worthy of worship.

• The third is to know that He alone bestows every outward and inward blessing, both religious and worldly. This obliges the heart to attach itself to Him in love and penitence, and to worship Him alone without partner.

• The fourth is what servants see and hear of the reward granted to His allies who uphold His monotheism: for example, the aid He grants to His messengers and their followers.