Matthew 6:21-23

for where your treasure is, there your heart [your wishes, your desires; that on which your life centers] will be also. “The eye is the lamp of the body; so if your eye is clear [spiritually perceptive], your whole body will be full of light [benefiting from God’s precepts]. But if your eye is bad [spiritually blind], your whole body will be full of darkness [devoid of God’s precepts]. So if the [very]light inside you [your inner self, your heart, your conscience] is darkness, how great and terrible is that darkness!