The eye is the lamp of the body. If your eyes are good, your whole body will be full of light.
Ὁ λύχνος τοῦ σώματός ἐστιν ὁ ὀφθαλμός· ἐὰν οὖν ὁ ὀφθαλμός σου ἁπλοῦς ᾖ, ὅλον τὸ σῶμά σου φωτεινὸν ἔσται·