And one [of the angels] called out to another and said,
"Holy, Holy, Holy, is the LORD of hosts,
The whole earth is full of His glory."
And the foundations of the thresholds trembled at the voice of him who called out, while the temple was filling with smoke. (please read vv. 1-5 again)
The holiness of God is the most unavoidable thing about Him!
In the Hebrew language that Isaiah used, saying a word twice magnifies its meaning greatly. In Isaiah 26:3 the word "peace" is used twice in the Hebrew, but in English we translate it "perfect peace".
If saying "holy" twice would mean "perfect holiness", what a huge emphasis it is when the angel says "holy, holy, holy"! Exposed to the fullness of God's being, that angel is overwhelmed with the inexpressible, unavoidable, irreducible, unutterable, perfect holiness of God and the fact that the holiness of God is His glory. In a voice that shakes the massive foundations of the temple he cries out, "Holy, Holy, Holy, is the LORD of hosts, the whole earth is full of His glory."
Isaiah never forgot it. The holy ‘different-ness' of God became one of the great themes of his life.
God wants to help you see His holiness today. Take some quiet time and just think about what Isaiah saw and heard, and ask God "the LORD of hosts" to show you His holiness.