What does Matthew 6:22 mean?

Jesus has just commanded His listeners to stop stockpiling treasure on earth. Instead, they should invest in building treasure in heaven. This is done by making right choices out of sincere devotion to God. He said that human hearts are found wherever a person's true treasure is (Matthew 6:19–21). His point is not that money is evil, or that Christians are obligated to poverty. Rather, it means that the priority of a believer's life ought to be honoring God, and serving Him, rather than accumulating temporary wealth (Matthew 6:24).

This and Matthew 6:23 will illustrate this point. Jesus calls the eye the lamp of the body. This is true physically, of course; all the light by which we see the world is perceived by using our eyes. Healthy eyes capture all the available light, giving that person a clear understanding of the world around them. Symbolically, functioning eyes allow the mind and body to be "full of light."

The mind and thoughts—our awareness of the outside world—depends on the light being perceived by the eyes. In the following verse, Jesus notes that the reverse is also true. Faulty eyes don't perceive and transmit light, effectively cloaking the inner and outer world in darkness for that person.

Scripture often uses light as a metaphor for truth, goodness, and understanding (Proverbs 4:18–19; Matthew 4:16; 5:13; John 8:12; 2 Corinthians 4:6). Jesus' point here is about perception. Focusing hope and aspirations on temporary, earthly treasure indicates greed or lack of faith in God to provide. This spiritual flaw is to the heart what a cataract or injury is to the eye. It effectively creates darkness, on the inside, by failing to perceive and transmit "light." Blocking the light of spiritual truth leads to inner darkness filled with moral corruption. It is like being blind.

On the contrary, focusing on sincere devotion to God and right living is like having clear, healthy eyes: it allows the light of God's righteousness into a person's heart.