From the 'Book of Foundations' (Kitab al-Usus):

The Sage (al-'Alim)—may His might be exalted—says: The questioner asked: 'Does every form have a fashioner (musawwir), and does every thing have an origin (mansha’)?' The Sage replied: 'There is a form that has a fashioner, and a form that has no fashioner. Likewise, there is a thing that has an origin, and a thing that has no origin.'

He says: 'The Form is more powerful than the Body. This is because that which has no form possesses no intellect, no understanding, and no speech. The "perfect body" is the one that possesses these attributes, which are among the attributes of the Form; whereas the "deficient body" has no [true] form. Furthermore, benefits are expected from the Form, while no benefit is expected from that which has no form.' He says: 'The Unique, the Creator, the Pre-eternal possesses a Form and an Appearance (hay’a) characterized by hearing, sight, and delineation; and the Spirit is His Appearance.'

He says: The Sage—may His might be exalted—said: 'The Form exists due to the need of the created beings for it, just as they need speech—for there is no speech except from a Form.'