Worship of the impersonal Divine Essence
Replacing the Father with a concept of the Divine Essence.
"And the LORD shall be king over all the earth: in that day shall there be one LORD, and His name one." Zech.14.9
Excellent protection against tritheism, modalism and Arianism, but does this diagram properly represent the Divine Being presented in Holy Scripture?
What is ousialatry?
The worship of an impersonal Divine essence uniting the three Persons of Deity, in which all three subsist, conceptually distinct from their subsistence in the Father Himself.
A message on the subject.
The related question of Divine Simplicity and a scriptural response.
Augustine on the the Theophany at Mamre (Gen.18)
The Oration on Holy Baptism section XLI (p.757 in the pdf file)