When you hear the word “holy” what comes to mind? Perhaps you think of purity and perfection. When it comes to the holiness of God, we need to think of distinctness and separation. While the word holiness encompasses the idea of perfection and purity—it likewise points to the distinct nature of God. When we think of God, we must think of the fact that God is outside of his creation, distinct from his creation, and transcends higher than everything in the universe. God is God and there is no being or created thing that can remotely compare to him. God is radiant in purity, majestic in perfection, and sovereign in power.
When King Uzziah died and all of Israel was looking to an empty throne for leadership, God pulled back the veil of eternity and allowed Isaiah to see the enthroned King of kings and Lord of lords. It was as if God were communicating to Isaiah that the King is not dead—he is enthroned—high and lifted up on his majestic and sovereign throne. In the first few verses of Isaiah 6, we see two distinct names for God—”אָדוֹן” (the sovereign name of God) and “יהוה” (the sacred name of God). What Isaiah sees is breathtaking.
Isaiah sees into the throne room of glory and his eyes are captivated by the seraphim that are flying around the throne crying out with these words, “Holy, Holy, Holy is the LORD of hosts, the whole earth is full of his glory” (Is. 6:3). As these echoes are hurled back and forth between the angelic beings, Isaiah takes note of what he sees. He sees the Lord of glory on his throne and the train of his robe filing the temple which I believe to be a reference to the throne room of heaven itself and a pre-incarnate vision of Jesus. They question remains, why did the angels cry out with the repetition of “holy, holy, holy” as they circled the throne of the King?
For the Purpose of Worship
The main purpose for the repetition of the word holy by the angelic beings must be centered on the goal of worship. Apparently, this was a routine day for the angels, but an extraordinary day for Isaiah. It appears that the angels are doing exactly what they were created to do—worship God. When John came into the presence of the angelic being and he fell down to worship the angel, but the angel rebuked him and directed him to worship God (Rev. 19:10). God desires for his creatures to worship him—both angels and humans. R.C. Sproul rightly explained the emphasis on God’s holiness by saying:
Only once in sacred Scripture is an attribute of God elevated to the third degree. Only once is a characteristic of God mentioned three times in succession. The Bible says that God is holy, holy, holy. Not that He is merely holy, or even holy, holy. He is holy, holy, holy. The Bible never says that God is love, love, love; or mercy, mercy, mercy; or wrath, wrath, wrath; or justice, justice, justice. It does say that he is holy, holy, holy, that the whole earth is full of His glory. 
God is worthy of worship. There is no shame in the amount of worship that’s given to God by the angels. They can’t worship God enough—even they must shield their face with two of their wings as they worship before the very throne of God. John Calvin writes, “The repetition of Holy, holy, holy points to unwearied perseverance, as if the prophet said that the angels never cease from singing the praises of God since God’s holiness supplies inexhaustible reasons for them.” 
For the Purpose of the Isaiah (and the readers of Isaiah’s Prophecy)
God sovereignly planned for Isaiah to see this glimpse of glory. It would serve two very distinct purposes. First of all, it would be used to solidify his call to be a prophet for God. When the earthly king was gone, Isaiah was able to see that the true King of kings is very much alive and reigning from heaven’s throne. This event left an indelible mark upon his soul. As he was seeing the transcendent King of glory worshipped by angels—he was overwhelmed with his depravity. He understood that he needed forgiveness. God forgave his sin and then Isaiah was ready to be sent by God, as he repeated—”Here I am, send me.”
The secondary purpose for the recording of this scene of heaven was for the readers of Isaiah’s prophecy—which would include us in our present day. Not only is God sovereign over providing the vision for Isaiah personally, but he’s sovereign to use this scene in a portion of the canon of Scripture that would forever be preserved through the ages. Although Isaiah 6 is not a personal vision for us—it’s recorded for us to see and understand the transcendent holiness of God and how he deserves to be worshipped.
In Hebrew, rather than underlining or using exclamation points—they would repeat something in order to give attention and add significance. Here we see the angels doing that very thing as they cried out, “Holy, holy, holy is the LORD of hosts.” As we read it today, we are reminded that God is the most holy being that is or every will be—and he alone deserves our worship. The most important truth that could occupy real estate in the mind of a human being is the holiness of God. From the holiness of God flows the love of God, the justice of God, and the mercy of God—along with all of the other attributes. God is God and he alone is worthy of our worship.
Holy, Holy, Holy! Lord God Almighty!
Early in the morning our song shall rise to Thee.
Holy, Holy, Holy! Merciful and mighty!
God in three persons, blessed Trinity!
—Reginald Heber (1826)
- R.C. Sproul, The Holiness of God (Carol Stream, IL: Tyndale House Publishers, 2000), 26.
- John Calvin, Isaiah, Crossway Classic Commentaries (Wheaton, IL: Crossway Books, 2000), 61.