Ὁ λύχνος τοῦ σώματός ἐστιν ὁ ὀφθαλμός. ἐὰν οὖν ⸂ᾖ ὁ ὀφθαλμός σου ἁπλοῦς⸃, ὅλον τὸ σῶμά σου φωτεινὸν ἔσται· ἐὰν δὲ ὁ ὀφθαλμός σου πονηρὸς ᾖ, ὅλον τὸ σῶμά σου σκοτεινὸν ἔσται. εἰ οὖν τὸ φῶς τὸ ἐν σοὶ σκότος ἐστίν, τὸ σκότος πόσον. (ΚΑΤΑ ΜΑΤΘΑΙΟΝ 6:22, 23 SBLG)
“The eye is the lamp of the body. So, if your eye is healthy, your whole body will be full of light, but if your eye is bad, your whole body will be full of darkness. If then the light in you is darkness, how great is the darkness! (Matthew 6:22, 23 ESV)
Most of the evangelical interpretations of this passage have applied it to pornography and other occasions of lust. Connections are made with Psalm 101:3 (“I will set nothing wicked before my eyes”) and Proverbs 4:25 (“Let your eyes look directly before you, and your gaze be straight ahead”).
Such applications are certainly wholesome. Yet they have always struck me as forced, robbing Jesus’ sermon (or Matthew’s report of it) of any flow. Neither the preceding passage (“Do not treasure up for yourselves treasures on the earth…”) nor the following one (“You cannot serve both God and Mammon”) has anything much to do with sins of sexual lust. Where’s the train of thought?
The answer – and it is readily available in good commentaries, so I cannot claim to be the discoverer of it – is that the OT and Jewish background gives a very different meaning to Jesus’ words in 6:22-23.
Deuteronomy 15:9 warns the Israelites against stinginess during the advent of the Sabbath year:
Take care lest there be an unworthy thought in your heart and you say, “The seventh year, the year of release is near,” and your eye be evil (wera’ah ‘eynekha) toward your poor brother, and you give him nothing, and he cry to the Lord against you, and you be guilty of sin. (Deuteronomy 15:9)
Likewise Dt. 28:54-56, speaking about the horrors of cannibalism in the straits of a siege:
The man who is the most tender and refined among you, his eye shall be evil (terah ‘eynow) to his brother, to the wife he embraces, and to the last of the children whom he has left, The most tender and refined woman among you, who would not venture to set the sole of her foot on the ground because she is so delicate and tender, her eye shall be evil (terah ‘eynah) to the husband she embraces, to her son and to her daughter… (Deuteronomy 28:54, 56 ESV)
The eye here is not the receptacle of bad influences coming in, but the portal of malice going out. (And such emissionistic theories of the eye’s operation were not unusual in be ancient world: Empedocles, for instance, compared the eye to a lantern with sides of horn, DK 31 B84, 87.) Jesus is talking about miserliness, begrudging, envy – Latin invidia, from in + videre, to look against, to give someone the evil eye. Pirke Avoth is the Rabbinic source that has the most to say about it, and all its uses are consistent with Jesus’ mention here in Matthew 6:
“he who desires to give, but that others should not give, his eye is evil toward what appertains to others; he who desires that others should give, but will not give himself, his eye is evil against what is his own…” m.Avot 5.15
“R. Joshua said, “The evil eye, the evil inclination, and hatred of his fellow-creatures, put a man out of the world.” m.Avot 2.16
““A good eye, a humble mind, and a lowly spirit (are the tokens) of the disciples of Abraham, our father; an evil eye, a haughty mind, and a proud spirit (are the signs) of the disciples of Balaam, the wicked.” m.Avot 5.19
We may fairly conclude that Jesus’ saying is about one’s attitude toward one’s fellow men. What, then, is meant by “if your eye is healthy, your whole body will be full of light”? Those who are generous to their neighbors are themselves in a good state with God: if you with your own lamp give light to others by giving generously to them, God will shine the light of His countenance upon you. With the measure you use, it will be measured to you.
The result of understanding this background in Hebrew idiom is a newly revealed consistency and rhetorical force to Jesus’ arrangement of His sermon, in perfect agreement with other statements from the same sermon. (And if you need to preach against looking at pornography, there are plenty of other passages to use.)