Prepare a way for the Lord. Brethren, we prepare the way of the Lord as we are bidden to do by walking along it; and we can walk along it only by preparing it. However far you journey along it, the way is always waiting to be prepared, so that you must start afresh from the place you have reached and advance along what lies ahead. You are led to do so because at every stage you meet the Lord for whose coming you are preparing the way, and each time you see him in a completely new way and as a much greater figure than you have met before. The just man has the right prayer when he says: Set your way which justifies as a law for me, Lord, and I will always seek after it.
It is therefore eternal life which is probably meant, because although a man can study his route with foresight and determine just how far he can go, from the very nature of goodness there is no limit to the way along which you travel. And so, when the wise and indefatigable traveler has reached his goal he will begin again: forgetting, that is, what lies behind him, so that each day he can say to himself: Now I begin.
Guerric of Igny, Fifth Sermon for Advent (Liturgical Sermons I, CF 8, p. 30)