The Sanctus is a very rich prayer when we consider what exactly is going on. Two scenes are called to mind in this prayer, both of which were introductions. The first is from the Prophet Isaiah:
I saw the Lord sitting upon a throne high and elevated: and his train filled the temple. Upon it stood the seraphims: the one had six wings, and the other had six wings: with two they covered his face, and with two they covered his feet, and with two they hew. And they cried one to another, and said: Holy, holy, holy, the Lord God of hosts, all the earth is full of his glory. And the lintels of the doors were moved at the voice of him that cried, and the house was filled with smoke. And I said: Woe is me, because I have held my peace; because I am a man of unclean lips, and I dwell in the midst of a people that hath unclean lips, and I have seen with my eyes the King the Lord of hosts.
And one of the seraphims flew to me, and in his hand was a live coal, which he had taken with the tongs off the altar. And he touched my mouth, and said: Behold this hath touched thy lips, and thy iniquities shall be taken away, and thy sin shall be cleansed. And I heard the voice of the Lord, saying: Whom shall I send? and who shall go for us? And I said: Lo, here am I, send me.I would like to submit that when Isaiah saw this vision, Isaiah saw the Mass. Remember, heaven cannot be measured via time, because it is outside of time. God is timeless. When he saw the angels in their chant, he was seeing yesterday, his present time, and several millennia later, right up to the present day. He states that he was in the temple. Temples are the place of sacrifice. The smoke from the incense filled the temple, and God himself was present. What he saw (but perhaps could not explain), was that God was present as both priest and victim. Recognizing the amazing event he witnessed, he saw how unworthy he was. Not only because he saw God, but rather that he saw God accomplish his ultimate plan, the salvation of the human race. As a result of this, an angel comes and purifies him, so that he can prepare worthily for the event he is about to witness.
The priest finds himself in a similar situation. After that purification (which we all receive in the Sacraments of Initiation), God asks for people to accept the calling of the priesthood. Not everyone will answer that call. When the priest does, he may ask, like Isaiah does, how long must he preach the Gospel? How long must he offer the Mass? The answer God provides is instructive:
Until the cities be wasted without inhabitant, and the houses without man, and the land shall be left desolate. And the Lord shall remove men far away, and she shall be multiplied that was left in the midst of the earth. And there shall be still a tithing therein, and she shall turn, and shall be made a shew as a turpentine tree, and as an oak that spreadeth its branches: that which shall stand therein, shall be a holy seedIn short, the priest is meant to act until the end of the world. Likewise, from the saying of the first Mass until the end of time, there will always be a priest somewhere, at some hour of the day, fulfilling the Lord’s request throughout the earth. This call remains equally true to the faithful, albeit in a different way. The Sanctus is a reminder that we too must live according to the Gospel to the end of the earth. The worship of God was meant for all creation. If one iota of creation is not yet participating in it, the job of a Christian is never done. Like Isaiah, we must realize our unworthiness to partake in the mystery of God’s redemption. This task is perfectly suited towards God. God is Holy. His very name is called Holy. When something was said three times in ancient times, it was a very special confirmation of what was being said.
Yet what makes the Canon such a holy thing? It is more than just our participation at Calvary. Through the Roman Canon, Holy Week itself is retraced.