It is not then without reason that in the mysteries that obtain among the Greeks, lustrations hold the first place; as also the laver among the Barbarians. After these are the minor mysteries, which have some foundation of instruction and of preliminary preparation for what is to come after; and the great mysteries, in which nothing remains to be learned of the universe, but only to contemplate and comprehend nature and things. We shall understand the mode of purification by confession, and that of contemplation by analysis, advancing by analysis to the first notion, beginning with the properties underlying it; abstracting from the body its physical properties, taking away the dimension of depth, then that of breadth, and then that of length. For the point which remains is a unit, so to speak, having position; from which if we abstract position, there is the conception of unity. If, then, abstracting all that belongs to bodies and things called incorporeal, we cast ourselves into the greatness of Christ, and thence advance into immensity by holiness, we may reach somehow to the conception of the Almighty, knowing not what He is, but what He is not. And form and motion, or standing, or a throne, or place, or right hand or left, are not at all to be conceived as belonging to the Father of the universe, although it is so written. But what each of these means will be shown in its proper place. The First Cause is not then in space, but above both space, and time, and name, and conception. Wherefore also Moses says, “Show thyself to me”[805]--intimating most clearly that God is not capable of being taught by man, or expressed in speech, but to be known only by His own power. For inquiry was obscure and dim; but the grace of knowledge is from Him by the Son. Most clearly Solomon shall testify to us, speaking thus: “The prudence of man is not in me: but God giveth me wisdom, and I know holy things.”[806] Now Moses, describing allegorically the divine prudence, called it the tree of life planted in Paradise; which Paradise may be the world in which all things proceeding from creation grow. In it also the Word blossomed and bore fruit, being “made flesh,” and gave life to those “who had tasted of His graciousness;” since it was not without the wood of the tree that He came to our knowledge. For our life was hung on it, in order that we might believe. And Solomon again says: “She is a tree of immortality to those who take hold of her.”[807] “Behold, I set before thy face life and death, to love the Lord thy God, and to walk in His ways, and hear His voice, and trust in life. But if ye transgress the statutes and the judgments which I have given you, ye shall be destroyed with destruction. For this is life, and the length of thy days, to love the Lord thy God.”[808]