Jesaja 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. 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 as with the doxologies of the Apocalypse, it had a certain historical significance in common with the whole scene. God is in Himself the Holy One (kâdōsh), i.e., the separate One, beyond or above the world, true light, spotless purity, the perfect One. His glory (Câbod) is His manifested holiness, as Oetinger and Bengel express it, just as, on the other hand, His holiness is His veiled or hidden glory. The design of all the work of God is that His holiness should become universally manifest, or, what is the same thing, that His glory should become the fulness of the whole earth (Isa 11:9; Num 14:21; Hab 2:14). This design of the work of God stands before God as eternally present; and the seraphim also have it ever before them in its ultimate completion, as the theme of their song of praise. But Isaiah was a man living in the very midst of the history that was moving on towards this goal; and the cry of the seraphim, in the precise form in which it reached him, showed him to what it would eventually come on earth, whilst the heavenly shapes that were made visible to him helped him…

Hitherto, it should seem, Isaiah had prophesied as a candidate, having only a virtual and tacit commission; but here we have him (if I may so speak) solemnly ordained and set apart to the prophetic office by a more express or explicit commission, as his work grew more upon his hands: or perhaps, having seen little success of his ministry, he began to think of giving it up; and therefore God saw fit to renew his commission here in this chapter, in such a manner as might excite and encourage his zeal and industry in the execution of it, though he seemed to labour in vain. In this chapter we have, I. A very awful vision which Isaiah saw of the glory of God (Isa 6:1-4), the terror it put him into (Isa 6:5), and the relief given him against that terror by an assurance of the pardon of his sins (Isa 6:6, Isa 6:7). II. A very awful commission which Isaiah received to go as a prophet, in God's name (v. 8), by his preaching to harden the impenitent in sin and ripen them for ruin (v. 9-12) yet with a reservation of mercy for a remnant, (v. 13). And it was as to an evangelical prophet that these things were shown him and said to him.

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; 4:4-7).