The entire life of a good Christian is holy desire. What you desire you do not yet see, but by desiring it you become capable of it so that when what you may see comes, you may be filled with it. If you want to fill a bag, and you know how big the thing is that will be given, you stretch the opening of the sack or the skin or whatever. You know how much you will put in it, and you see how narrow the bag is, and you make it more capacious by stretching it. So God by deferring our desire stretches it, and by the desiring stretches our mind, and by stretching it makes it more capacious. Let us desire, therefore, because we are going to be filled. See Paul stretching his bag so that it can receive what is coming: “Not that I have already received, or am already perfect, brethren; I do not think that I have already apprehended it.” What are you doing in this life, then, if you have not yet apprehended? “But this one thing I do: forgetting the things that are behind, stretched toward the things that lie before, I strain to follow on to the prize of the high calling” (Ph 3:13-14). He said he was stretching, said he was straining to follow on. He felt himself too little to receive “what eye has not seen nor ear heard nor ever ascended into the heart of man” (1 Cor 2:9).
This is our life: to be exercised by desiring. And holy desire exercises us to the degree that we prune our desires of love of the world. We have already said it: “Empty out what is going to be filled.” You are going to be filled with the good; then empty out the bad. Imagine that God wishes to fill you with honey; if you are full of vinegar, where will you put the honey? What the vessel contained has to be poured out, and the vessel itself cleaned, cleaned even it this takes effort, requires scrubbing, to be fit for that thing, whatever it is. We speak improperly when we call it gold, or wine. Whatever we call what cannot be named, whatever we wish to call it; it is called “God”. And what have we said when we say “God”? Is that one syllable the whole of what we are looking for? Whatever we have been able to say falls short of it: let us stretch ourselves towards him so that he may fill us when he comes. For “we shall be like him because we shall see him as he is.” (Augustine on I John, Hom. 4, 6 ; PL 35, 2009)