Gregory of Nazianzus
Catena Aurea · Lukasevangelium 11
No man, when he hath lighted a candle, putteth it in a secret place, neither under a bushel, but on a candlestick, that they which come in may see the light. The light of the body is the eye: therefore when thine eye is single, thy whole body also is full of light; but when thine eye is evil, thy body also is full of darkness. Take heed therefore that the light which is in thee be not darkness. If thy whole body therefore be full of light, having no part dark, the whole shall be full of light, as when the bright shining of a candle doth give thee light.
(Epist. 41.) Or else; The light and eye of the Church is the Bishop. It is necessary then that as the body is rightly directed as long as the eye keeps itself pure, but goes wrong when it becomes corrupt, so also with respect to the Prelate, according to what his state may be, must the Church in like manner suffer shipwreck, or be saved.