Luke 11:33-36

33"No one after lighting a lamp puts it in a cellar or under a basket, but on a stand, so that those who enter may see the light.

34Your eye is the lamp of your body. When your eye is healthy, your whole body is full of light, but when it is bad, your body is full of darkness.

35Therefore be careful lest the light in you be darkness.

36If then your whole body is full of light, having no part dark, it will be wholly bright, as when a lamp with its rays gives you light."