Indwelling is of two kinds: restricted and unrestricted.

Restricted indwelling is the doctrine of the Christians and others like them, including extremists among the Rāfidah (Rejectionists), those who go to extremes in worship, and others. They say that He dwelt in Christ or united with him, and dwelt in ʿAlī or united with him, and that He unites with the gnostics until the one affirming His oneness becomes the One whose oneness is affirmed. They say:

“No one has affirmed the oneness of the One,
For everyone who has found Him denies Him.
The affirmation of His oneness by one who speaks of His attributes
Is a loan annulled by the One.
His affirmation of His own oneness is affirmation indeed;
The description offered by one who benefits Him goes astray.”

These are the people whose statement Ahmad reported:

“When Allah wishes to bring something about, some of His creation enters into it, and He speaks through its tongue.”

I have met more than one of these people who addressed me and discussed this doctrine with me, and I explained its invalidity to them.

As for the proponents of unrestricted indwelling, who say that He dwells in everything, is united with everything, or that existence is one—such as the followers of Fusūs al-Hikam (The Bezels of Wisdom) and others like them—they say that the Christians erred by restricting it to particular beings. Likewise, they say that idol worshippers erred by singling out certain things and worshipping them.

I have also met more than one of these people, and we were involved in a well-known ordeal with them.