In paragraph 33, Augustine says that all the truths about sense perceptions and mental perceptions are one. This judgment that such and such is true applies to each and every single truth. Thus there is, in his estimation, a unity of truth, something that runs through every individual truth. He refers to this underlying truth as wisdom or Truth Itself. According to Augustine, Truth Itself and the rules of truth are superior to our minds because they direct our minds.
Truth is our guide.
Augustine talks about the happiness and pleasure that we can obtain by contemplating Truth Itself. He considers Truth Itself to be our chief good. The question was raised above whether we could equate eternal and unchanging truth with God. Notice that Augustine considers truth to be a good. For him, it is an existing thing.