9 What then? When he has brought us to such a height as this, is he in truth able to stop us there? By no means; but just as one by transporting into the midst of the sea a person who was standing on the beach, and looking on cities, and beaches, and havens, removes him indeed from the former objects, yet does not stay his sight anywhere, but brings him to a view without bound; so this Evangelist, having brought us above all creation, and escorted us towards the eternal periods which lie beyond it, leaves the sight suspended, not allowing it to arrive at any limit upwards, as indeed there is none.
For the intellect, having ascended to “the beginning,” enquires what “beginning”; and then finding the “was” always outstripping its imagination, has no point at which to stay its thought; but looking intently onwards, and being unable to cease at any point, it becomes wearied out, and turns back to things below. For this “was in the beginning,” is nothing else than expressive of ever being and being infinitely.
Do you see true philosophy and divine doctrines? Not like those of the Greeks, who assign times, and say that some indeed of the gods are younger, some elder. There is nothing of this with us. For if God Is, as certainly He Is, then nothing was before Him. If He is Creator of all things, He must be first; if Master and Lord of all, then all, both creatures and ages, are after Him.
Source: Homilies on the Gospel of John (New Advent)