“Holy, Holy, Holy, Lord God the Almighty”+
Although these words are from the book of Revelation in the New Testament, the same tripled ascription of holiness to God is found in the Old Testament (Isaiah 6.3). Christians have always seen this “Tersanctus” (Latin) or “Trisagion” (Greek) as hinting at the doctrine of the Trinity in both Testaments. But it might seem to many people that this would be “drawing a long bow”, especially in the Old Testament context. That is, it may seem to be reading more into the words than is there.
But the amazing thing is that, despite the deep monotheism of the Old Testament, and its repeated and angry denunciation of worshippping any but the one true God, strong hints of Trinitarian concepts are found there. And so, once this is realised, it becomes much less of a stretch to see the Tersanctus as Trinitarian worship.
These strong hints may be found in the very first chapter of the Scriptures. In Genesis 1 the first three verses seem to differentiate between God and his Spirit, and make the Word of God to be creative. God then says “Let us make man in our image” in verse 26. And the very word for God used here, Elohim, is a plural form. Now, none of this on its own proves the doctrine of the Trinity, and it has been argued that the plurals used are plurals of majesty, such as earthly kings (and bishops!) use. But it is all consistent with the doctrine, and there is more to come.
The great declaration of the unity of the God of Israel is the Shema, which I recite as the beginning of the Two Great Commandments at the beginning of each Mass: “Hear O Israel, the Lord our God is one Lord”. But the word used here for “one” is not the word always meaning absolute oneness, yachid, but one which can mean unity within plurality, echad. One of the many examples of the latter word being used this way elsewhere in the OT is back in Genesis again, 2.24: “a man will leave his father and mother and be united to his wife, and they will become one [echad] flesh”.
There are also examples in the OT where a particular being is spoken of as if divine, called God, or even worshipped, yet is often distinguished also in some way from God, even by him speaking of God in the third person. In Genesis 18.17-19 we have this statement by one in the appearance of a man: “Then the LORD said, "Shall I hide from Abraham what I am about to do? ... For I have chosen him, so that he will direct his children and his household after him to keep the way of the LORD by doing what is right and just, so that the LORD will bring about for Abraham what he has promised him."” This kind of thing happens repeatedly in the case of the “angel of the LORD” (e.g., Genesis 16.7-13; 22.11-18; Exodus 3.2-6; 23.20-23; Judges 6.11-14, 20-22; 13.21-23, 1 Chronicles 21.15). For example, the prophet Hosea, recounting the experience of Jacob's wrestling with the Angel, says the following about this being: “as a man he struggled with God. He struggled with the angel and overcame him; he wept and begged for his favor. He found him at Bethel and talked with him there --the LORD God Almighty” (12.3-5).
A number of Messianic prophecies forced the ancient Jewish rabbis to consider the Messiah as having greater than human or angelic status and to ascribe to him divine qualities such as eternity. For example, how else is one to understand these passages? “Your throne, O God is for ever and ever ... that is why God, your God, has anointed you above your fellows” (Psalm 45.6,7). “Unto us a Son is given ... and he shall be called ... Mighty God, Everlasting Father” (Isaiah 9.6).
And then there prophetic passages which bring the three members of the Trinity together. In Isaiah 48 one who earlier calls himself “the first and the last” and who created heaven and earth (v. 12,13) goes on to say: “Come near to Me, listen to this: From the first I have not spoken in secret, From the time it took place, I was there. And now the Lord GOD has sent Me, and His Spirit.” Similarly, Isaiah 63.9-10, in speaking of God's difficult relationship with his ancient people says this: “the angel of His presence saved them ... But they rebelled and grieved His Holy Spirit”. Zechariah 12.10 has this: “And I will pour out on the house of David and on the inhabitants of Jerusalem, the Spirit of grace and of supplication, so that they will look on Me whom they have pierced; and they will mourn for Him, as one mourns for an only son”.
It is the combination of such plentiful and surprising implicit evidence for the doctrine in the OT with the clear lack of explicit conscious realisation of it by the human authors and readers of the time that is so powerfully impressive. Here we have beautiful evidence, for those willing to see, not only for the doctrine of the Trinity, but for the fact that the Scriptures transcend the human instruments used to write them. They truly are the word of God. And it is not as if the later doctrine of the Trinity was built in order to make sense of these Scriptures (especially as their significance took time even for the Church to draw out). Instead, it grew out of the disciples' experience of Jesus and his teaching and their experience of the Holy Spirit, both in their midst, both bringing them to the Father. It is this which shows we have, in a sense, independent lines of evidence, or witnesses to this doctrine. Finally, the very fact that even the NT evidence is mostly implicit, and yet the doctrine is so clearly fundamental and is taught and explicated by the Catholic Church, gives testimony to the necessity of the Church for interpreting the Scriptures safely and fruitfully.
So, let us rejoice in the marvellous way God has revealed Himself in Tri-Unity, and, still more, let us adore Him who is Holy, Holy, Holy. +