Iudica me, Deus, et discerne causam meam de gente non sancta: ab homine iniquo et doloso eripe me: quia tu es Deus meus, et fortitudo mea. -- from the Introit for Passion Sunday
...antequam Abraham fieret, ego sum.("Before Abraham was, I am") -- from the Gospel for Passion Sunday.
This name HE WHO IS is most properly applied to God, for three reasons:
First, because of its signification. For it does not signify form, but simply existence itself. Hence since the existence of God is His essence itself, which can be said of no other, it is clear that among other names this one specially denominates God, for everything is denominated by its form.
Secondly, on account of its universality. For all other names are either less universal, or, if convertible with it, add something above it at least in idea; hence in a certain way they inform and determine it. Now our intellect cannot know the essence of God itself in this life, as it is in itself, but whatever mode it applies in determining what it understands about God, it falls short of the mode of what God is in Himself.
Therefore the less determinate the names are, and the more universal and absolute they are, the more properly they are applied to God. Hence Damascene says that, "HE WHO IS is the principal of all names applied to God; for comprehending all in itself, it contains existence itself as an infinite and indeterminate sea of substance."
Now by any other name some mode of substance is determined, whereas this name HE WHO IS, determines no mode of being, but is indeterminate to all; and therefore it denominates the "infinite ocean of substance."
Thirdly, from its consignification, for it signifies present existence; and this above all properly applies to God, whose existence knows not past or future, as Augustine says.
Saint Thomas Aquinas
Recognize the Creator -- distinguish the creature. He who spoke was made the seed of Abraham; and that Abraham might be made, He Himself was before Abraham.
Hence, as if by the most open of all insults thrown at Abraham, they were now excited to greater bitterness. Of a certainty it seemed to them that Christ the Lord had uttered blasphemy in saying, "Before Abraham was made, I am." "Therefore took they up stones to cast at Him."
To what could so great hardness have recourse, save to its like? "But Jesus" as man, as one in the form of a servant, as lowly, as about to suffer, about to die, about to redeem us with His blood; not as He who is -- not as the Word in the beginning, and the Word with God.
For when they took up stones to cast at Him, what great thing were it had they been instantly swallowed up in the gaping earth, and found the inhabitants of hell inplace of stones? It were not a great thing to God; but better was it that patience should be commended than power exerted.
Saint Augustine
