Isaiah 6:3

“And one cried unto another, &c.] This denotes the publicness of their ministry, and their harmony and unity in it; they answered to one another, and agreed in what they said; their preaching was not yea and nay, (<470119>2 Corinthians 1:19): and said, holy, holy, holy [is] the Lord of hosts; this expresses the subject matter of the Gospel ministry, respecting the holiness of God; all the doctrines of the Gospel are pure and holy, and have a tendency to promote holiness of heart and life, and are agreeable to the holiness of God, and in them the holiness of God in each of the divine Persons is declared; particularly the Gospel ministry affirms that there is one God, who is the Lord of hosts,…”

“(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).”

“And one cried to another - Hebrew ‘This cried to this.’ That is, they cried to each other in alternate responses. One cried ‘holy;’ the second repeated it; then the third; and then they probably united in the grand chorus, ‘Full is all the earth of his glory.’ This was an ancient mode of singing or recitative among the Hebrews; see Exodus 15:20-21, where Miriam is represented as going before in the dance with a timbrel, and the other females as following her, and “answering,” or responding to her, Psalms 136:1; compare Lowth, “on the Sacred Poetry of the Hebrews,” Lect. xix. Holy, holy, holy - The “repetition” of a name, or of an expression, three times, was quite common among the Jews.…”

“Cried - Singing in consort. Holy - This is repeated thrice, to intimate the Trinity of persons united in the Divine essence. Glory - Of the effects and demonstrations of his glorious holiness, as well as of his power, wisdom, and goodness. Isaiah 6:4”

“6:3 The triple usage of the word holy emphasizes the absolute separateness of the Lord. • The whole earth is filled: Because there is no verb in the Hebrew, two slightly different translations of the seraphim’s proclamation are possible. It could be that the earth, though defiled, is currently filled with his glory in creation. Or, it could mean that the earth will be filled with the glory of the Lord when he establishes his kingship on the earth in the future. Either way, the Lord’s glorious presence will one day dwell more fully on earth, despite humanity’s sinfulness and the power of wicked nations. God’s glory was further revealed in the incarnation of the Son (John 12:41; 2 Cor 3:18;…”

“one cried unto another: Heb. this cried to this, Exo 15:20, Exo 15:21; Ezr 3:11; Psa 24:7-10 Holy: Exo 15:11; Rev 4:8, Rev 4:9, Rev 15:3, Rev 15:4 the whole earth: etc. Heb. his glory is the fulness of the whole earth, Isa 11:9, Isa 11:10, Isa 24:16, Isa 40:5; Num 14:21; Psa 19:1-3, Psa 57:11, Psa 72:19; Hab 2:14; Zac 14:9; Eph 1:18 Isaiah 6:4”

“"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. One set commenced, and the others responded, either repeating the "Holy, holy, holy," or following with "filling the whole earth is His glory." Isaiah heard this antiphonal or "hypophonal" song of the seraphim, not merely that he might know that the uninterrupted worship of God was their blessed employment, but because it was with this doxology…”