Remigius of Auxerre
Catena Aurea · Matthäusevangelium 6
The light of the body is the eye: if therefore thine eye be single, thy whole body shall be full of light. But if thine eye be evil, thy whole body shall be full of darkness. If therefore the light that is in thee be darkness, how great is that darkness!
(ap. Gloss. ord.) Otherwise; faith is likened to a light, because by it the goings of the inner man, that is, action, are lightened, that he should not stumble according to that, Thy word is a light to my feet. (Ps. 119:105.) If that then be pure and single, the whole body is light; but if defiled, the whole body will be dark. Yet otherwise; by the light may be understood the ruler of the Church, who may be well called the eye, as he it is that ought to see that wholesome things be provided for the people under him, which are understood by the body. If then the ruler of the Church err, how much more will the people subject to him err?