Matthew 6:22

22TheὉlampλύχνοςof theτοῦbodyσώματόςisἐστινtheὁeyeὀφθαλμός.Ifἐὰνthereforeοὖνisᾖtheὁeyeὀφθαλμόςof youσουclearἁπλοῦς,[the] wholeὅλοντὸbodyσῶμάof youσουfull of lightφωτεινὸνwill beἔσται·

The lamp of the body is the eye. Therefore if your eye is sound, your whole body will be full of light.