Concerning what the questioner has asked regarding the statement of the philosophers that "the uncompounded reality is all things", say: know that what is intended by "things" in this context is none other than being and the perfections of being in so far as they are existent [and not privative]; and by "all" is meant the obtainer. This "all" contains no plurality and no part of it can be compared to the whole. The meaning is that the uncompounded reality, insofar as it is uncompounded in all respects, is the obtainer and gatherer of all the infinite and endless perfections. As it has been said: "His works are limitless."
In the Persian language, it may be said that what the philosopher means by the word "things" in the afore-mentioned expression is the perfections of being in so far as these are existent [and not privative]; and by the word "all", is meant possession that is to say obtaining -- the gathering together of all of the limitless perfections, in an uncompounded manner. They have mentioned similar things throughout their discourse on the Divine unity, power, and intensity of existence.
The meaning of the philosopher was not that the Necessarily Existent [God] has become dispersed among the innumerable existent things. No! Praised be He! Exalted is He above that! Even as the philosophers themselves have stated: "The uncompounded reality is all things, but is not any one thing."
- Baha’u’llah
(‘Tablet of the Uncompounded Reality’)