Isaiah 6:3, “And one called to another and said, ‘Holy, holy, holy is YHWH of hosts; the whole earth is full of His glory!’”
In Scripture, holiness is often associated with otherness and separateness (a holy vessel is separate from common vessels etc.), so we might assume that the perfect (threefold) holiness of YHWH would mean the perfect separation of YHWH from all else. Of course, in a way this is true—YHWH is not merely the highest in a chain of being, He is Creator and all else is Creation; He is essentially holy, all other “holy ones” are derivatively holy.
And yet, notice that the exposition of YHWH’s threefold holiness in v.3 tells us that “the whole earth is (or will be) filled with His glory (“glory” being the external manifestation of His internal beauty; of “who he is”). So here it would seem that perfect holiness—far from forming a dividing wall between God and creation—actually leads to the saturation of creation with God. YHWH is perfect in holiness and—as the expression of that holiness / as the exposition of what perfect holiness is—the entirety of the created world is and will be filled with His beauty, which is to say, filled with HIMSELF.
Perfect holiness is, then, perfect self-giving, perfect communication of God, which is to say, perfect LOVE. Ultimately, Holiness is love (foundationally the personal love of God for God within the Trinity). Therefore, perfect holiness is perfect love, and perfect love (as we see on Calvary) is the unreserved giving of God’s self so that the beloved may be satisfied—filled—with God.
The perfection of holiness—the perfection of love—of which the seraphim sing and by which all creation is being and will be “filled” with the glory of YHWH, is revealed in the self-giving of Jesus Christ on the cross. Yes—when the incarnate Son is high and lifted up (Is.6:1; 52:13; Jn.8:28, etc) on the throne of Calvary, that is when the perfect holiness of YHWH sung about in Isaiah 6:3 is on full display…and it is by the revelation of that holiness—that love—that the whole earth has beheld & is being filled & will one day be filled with the glory / beauty / name of YHWH, just as the waters cover the sea (Is.9:11).
