I wrestled with Matthew 6:22-23–within the context of Matthew 6:19-34–until it yielded some of its fruits.
22 “The eye is the lamp of the body. So, if your eye is healthy, your whole body will be full of light, 23 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! (Matt. 6:22-23, emphasis added)
The “eye” is the entry point here. “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.” Whatever the eye focuses on, affects the rest of the body. This I believe continues the theme of the previous paragraph: “For where your treasure is, there your heart will be also” (v.21, emphasis added).
And we see the same theme continuing in the next paragraph (v. 24): “You cannot serve God and money,” with “money” representing materialism and the like. We are called to exclusive devotion to the Lord.
Next, we find an application of this principle of sole devotion to God while trusting him to provide for those things we are often anxious about, and which often divide and distract our attention from sole devotion to God–from verses 25 to 34.
Rather than being anxious about food and clothing, following the indictment of our Lord, “O you of little faith,” we find the corrective to our tendency toward anxiousness:
“But seek first the kingdom of God and his righteousness, and all these things will be added to you” (v. 33).
Therefore to maintain a healthy eye, to set our heart on heavenly things, to serve God exclusively, we must “seek first the kingdom of God and his righteousness, and all these things will be added to you.”