Ambrose of Milan
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.
Either faith is the light, as it is written, Thy word, O Lord, is a lantern to my feet. (Ps. 119:105.) For the word of God is our faith. But a lantern cannot shine except it has received its quality from something else. Hence also the powers of our mind and senses are enlightened, that the piece of moneywhich had been lost may be found. Let no one then place faith under the law, for the law is bound by certain limits, grace is unlimited; the law obscures, grace makes clear.