Each of these aspects of the Trinity that man images (existence, knowledge, and love) we see in man and in the world. We know, for example, that existence is intrinsically a good thing by how tenaciously both we and the animals hold on to it. Even when our lives are miserable, we beg for just a bit more; and if given the choice, we would always choose an eternity of misery over non-existence.
Likewise, we can see that we love to know, for "there is not a man who would not rather be sad but sane than glad but mad." Even the animals, though they cannot actually know, but only image knowledge, clearly delight in what small bit of knowledge they can participate in. We of course delight both in that knowledge which flows from our instincts and in that knowledge which is of a spiritual nature, "and by which we distinguish what is just from what is unjust--justice by means of an intellectual conception; what is unjust by the lack of such a form." We do not posses this knowledge through our senses, but rather through our sense of existence and our delight in knowledge itself. We love existence and knowledge, and there we have the three parts of mankind (love, existence, and knowledge) that form our image of the Trinity.
Augustine says that he does not need to go into the nature or depths of our "love for existence and knowledge, nor of the analogy to this love which can be found even on the lower levels of creation." It is enough to see that at root, what matters is the nature and focus of our love: "We do not call a man good because he knows what is good, but because he loves it." That is, we are to be judged according to the nature of our love--its orientation and focus. We can of course either love the good, or love "what should not be loved," or both. Animals and plants, for example, love the physical life. The inanimate world too is driven by love, though of course it is not aware of such a drive. But as men we have a higher sense of how love pervades the world:
It is, therefore, because we are men, created to the image of a Creator, whose eternity is true, His truth eternal, His love both eternal and true, a Creator who is the eternal, true, and lovable Trinity in whom there is neither confusion nor division, that, wherever we turn among the things which He created and conserved so wonderfully, we discover His footprints, whether lightly or plainly impressed. For, not one of all these things which are below us would either be, or belong to a particular species, or follow and observe any order, unless it has been created by Him whose existence, wisdom, and goodness are all transcendent.When we see God's providential government over the world, we should not see a cold and distant Stoic fate, an Aristotelian lonely contemplator of himself, a divine watchmaker, an impersonal Epicurean chance, a separated Platonic idea, or an abstract Pythagorean algorithm. We should see a God whose rule over Creation is shaped by a personal and intimate love.
The good news is that as believers, we participate in this love and look forward to the day when it will fully shape and direct our lives: "In Him our existence will know no death, our knowledge embrace no error, our love meet no resistance." We know this now by self-examination to a limited extent, but we ourselves are untrustworthy as final standards. (Augustine doesn't make the point, but it should be self-evident: every time we look at our own hearts for evidence of salvation, we are going to come away disappointed, because in this life we will always see sin there. And so we must lift our eyes from ourselves and to Jesus, who is the source, shaper, and goal of our faith and through whose work alone we have the hope of salvation.) Yet, God has not left us without guides--"we seek for other witnesses if we have not already found them."
Augustine does not discuss these witnesses here (frustratingly, in my opinion), but instead continues to focus on the City of God as it currently resides in heaven. Specifically, he continues his discussion of the angels.
The angels "know" God in a way which is purer and brighter than what we now can conceive. Specifically, they "know" God both in the sense that they can know Him in their own thoughts through self-examination, and in the sense that they can look at Him any time they please. Their knowledge of God is thus comparable to how we can both look at a line and mentally picture a line--the former is greater and purer than the latter, but both are forms of knowledge. But this is not just true of self-reflection, it is true of all creation. That is, the angels can look at themselves, mankind, the heavens, the earth, the animals, and so on, and see in all of these things something of God's character, but they know them more richly and fully when they see them in the Word of God, when they look to His Wisdom and see there that of which creation is only an image:
In the one case [looking to the Word of God], the knowledge [of the angels] has the clarity of the Artist's thought; in the other, it has shadows of the thing produced. But, when these creations are referred to the praise and adoration of the Creator Himself, it is as if the morning dawned in the minds of those who were contemplating them.Augustine has a simply wonderful point here: when we look to the world we do see something true about God, we see truth in that there is existence, wisdom, and love, but when we look at God in His Word, we see the Existence, Wisdom, and Love that created the world in its--in His--pure and primal nature. It is the difference between looking at a blurry photograph and looking at the person himself; certain true things may be had from the former, but the latter must be used as the standard and source. In the same way, if we want to understand the world, to exist, know, and love, we must look not at the world, but follow the example of the angels (surely one group of "witnesses" mentioned in the previous chapter) and look at God Himself in Jesus Christ, through whom alone we can have the true understanding, existence, and love that human beings are intended to have.