And one cried unto another, and said, Holy, holy, holy, is the LORD of hosts: the whole earth is full of his glory.
All Commentaries on Isaiah 6:3 Go To Isaiah 6
Pseudo-Dionysius the Areopagite
AD 550
The scriptural declaration “they cried out to one another” means, I think, that they ungrudgingly impart to each other the conceptions resulting from their looking on God. And we should piously remember that in Hebrew the Scripture gives the designation of seraphim to the holiest of beings in order to convey that these are fiery hot and bubbling over forever because of the divine life which does not cease to bestir them.
