Do not lay up for yourselves treasures on earth, where moth and rust destroy and where thieves break in and steal, but lay up for yourselves treasures in heaven, where neither moth nor rust destroys and where thieves do not break in and steal. For where your treasure is, there your heart will be also. 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! No one can serve two masters, for either he will hate the one and love the other, or he will be devoted to the one and despise the other. You cannot serve God and money. (Matthew 6:19-24 ESV)
Throughout the Sermon on the Mount, Jesus is showing us contrasts. All the contrasts are between the natural man and the regenerate man; the city of man versus the city of God; the broad road versus the narrow road; the things that are possible with man versus the things that are possible only with God.
In the above section Jesus calls us to look at two treasures, two eyes, and two masters. The first comparison is between laying up two treasures. The implication is that everyone is laying up treasure; because your “treasure” is whatever you value and cherish, and everyone will work to “lay up”, to get more of, whatever they value and cherish. If you value knowledge, you will go to college. If you value money, you will do whatever you can to make it.
Jesus first gives a command, to “lay up treasures in heaven”, and then the wisdom behind it, because the treasures of this life are doomed to pass away. But then he brings it back (as always), to the heart. I like John Michael Talbot’s paraphrase in one of his songs, “For wherever your treasure is, there will you find your heart.” You don’t have to wonder where you heart is; for it is revealed by where your treasure is. There are two applications to this insight: (1) The unbeliever is forced to look at where his heart truly is by his labor and (2) the believer is warned that following the broad road of treasuring the things of the earth will pull his heart away from where it needs to be, and encouraged to the wisdom of treasuring the things of heaven.
The second comparison is between two eyes. Here again we are talking about what we value and cherish; but in this comparison it is not what we are laboring for, but what we are lusting for. Both the eye and body mentioned are spiritual, not literally physical. If our spiritual eye is healthy and looking toward the light of the glory of God, the result will be a body full of light, full of God’s glory in every facet of our soul. On the other hand, the eye of the unregenerate looks only into darkness, and cannot see the light of God’s glory, which leaves his whole soul in darkness. As with the two treasures, the lesson of the eye judges the unbeliever of his blindness while the believer is encouraged and warned as to where his gaze should rest.
Finally, Jesus concludes by contrasting two masters. Here again, there are only two possibilities, and Jesus makes it plain that everyone serves one and only one. The earthly man is judged and found wanting, while the child of God is reminded whose he is.
So, where are you? If you look at yourself and cannot see that your heart treasures the things of God and labors for them, that your soul is filled with the light of the glory of God, that your service belongs to God alone, then you must judge that regardless of anything you may have said or done or thought, you must see that you are not truly a Christian. God calls you to repent, to turn, to see and embrace the wondrous glory of the gospel.
However, if you look at yourself and see the beginnings of those workings, of treasuring heaven, of light in your soul, of the lordship of Christ, then God beckons you onward, to deeper and deeper worship of Him, fellowship with Him, and obedience to Him as you journey towards Christ.