We have been made light out of darkness as the Apostle says: For once you, were darkness, but now you are light in the Lord; walk as children of light. He says another time: For you are not sons of the light and of darkness, but you are all sons of light and of the day. Saint John also rightly asserts in his letter: God is light, and whoever abides in God is in the light just as God himself is in the light. Therefore, because we rejoice in having been freed from the darkness of error, we should always walk in the light as children of light. This is why the Apostle says: Among them you shine as lights in the world, holding fast to the word of life.
-- Saint Chromatius of Aquileia from a discourse on the Gospel of Saint Matthew