And they were calling out to one another: “Holy, holy, holy is the LORD of Hosts; all the earth is full of His glory.”
The vision which Isaiah saw when he was, as is said of Samuel, established to be a prophet of the Lord (Sa1 3:20), was intended, 1. To confirm his faith, that he might himself be abundantly satisfied of the truth of those things which should afterwards be made known to him.
Commenting on Isaiah 6:1-4
Isa 6:3 “And one cried to the other, and said, Holy, holy, holy is Jehovah of hosts: filling the whole earth is His glory.” The meaning is not that they all lifted up their voice in concert at one and the same time (just as in Psa 42:8 el is not used in this sense, viz., as equivalent to C'neged), but that there was a continuous and unbroken antiphonal song.
(Rev 4:8). The Trinity is implied (on "Lord," see on Isa 6:1). God's holiness is the keynote of Isaiah's whole prophecies. whole earth--the Hebrew more emphatically, the fulness of the whole earth is His glory (Psa 24:1; Psa 72:19).