Luke 11:34-36

34The lamp of the body is the eye: therefore when thy eye is clear, thy whole body also is full of light; but when thy eye is bad, thy body also is full of darkness. 35Take heed therefore that the light which is in thee be not darkness. 36If 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 lamp doth give thee light.1