It is to Christ that the guiding star leads us, proclaiming him and pointing him out. It proclaims him in its appearing and points him out by going ahead and standing over the house where he is.
Now the star which leads us to Jesus is sacred scripture. Behold, our light has already come because for us and for our salvation God has become man. He was seen on earth and dwelt among men and women, so that, by the might of his Word and the example of his life, he might enlighten those who are sitting in darkness and direct them onto the way of peace. It is no wonder that before the Lord’s coming–when they had heard nothing of God, when they did not discern the light of Scripture–the pagans lay prostrate in their sins and the darkness of their errors.
But lying prostrate in carnal desires and in the darkness of iniquities is a matter for agitation, for the true light that enlightens everyone coming into this world, Jesus Christ, has now come. We cannot have further excuse for our sins, for Christ, who takes away the sins of the world and justifies the wicked, now speaks to us openly. Whoever follows me does not walk in darkness but will have the light of life.
From Aelred of Rievaulx’s “Sermon Four: For the Epiphany of the Lord”, The Liturgical Sermons, CF 58, p.116f