InEc 5:10-16, Solomon described the problem with earthly treasures...
Money and abundance do not truly satisfy
The abundance of the rich prevent good sleep, and often hurts the owner
Riches perish through misfortune, and cannot be taken with us when we die
InMt 6:19-21, Jesus commands us to lay up treasure not on earth, but in heaven...
Likely a Hebrew idiom, in which a contrast is made for the sake of emphasis - cf.Jn 6:27
Not that it is wrong have earthly treasures per se, but our focus should be on laying up treasure in heaven
[Why should our focus be on laying up treasure in heaven? Also, how do we lay up treasure in heaven? InMt 6:19-24, Jesus tells us...]
REASONS TO LAY UP TREASURE IN HEAVEN
TREASURE ON EARTH IS INSECURE...
Moth and rust destroy (material things are perishable)
Thieves break in and steal (material things are subject to theft)
There is also loss due to inflation, stock devaluation, bankruptcies, faulty investments, etc.
TREASURE IN HEAVEN IS SECURE...
Neither moth nor rust destroys (our treasures are imperishable) - cf.1Pe 1:3-4
Thieves can not break in and steal (our treasures are securely guarded) - cf.1Pe 3:4-5
OUR TREASURE IS WHERE OUR HEART WILL BE...
That is, where our affections, our hopes, our dreams will be
If our treasure is on earth, our hearts will experience much disappointment
As things for which you have affection decay or are one day destroyed by fire
As things in which you find your primary joy are suddenly gone through things like theft
If our treasure is in heaven, our hearts will not suffer great disappointments
For our treasure is "incorruptible, undefiled, and does not fade away"
Nothing can take our treasure away from us, for it is:
"reserved in heaven for you"
"kept by the power of God through faith"
Whatever happens on earth will not devastate us! - e.g.,He 10:32-34
When these words are taken to heart and applied
The storms of life will not overwhelm us
Because we've built our foundation upon the words of Jesus! - cf.Mt 7:24-27
TO KEEP OUR EYE GOOD...
Understanding the metaphor used by Jesus:
The "body" likely represents the soul or inner man
The "eye" likely represents the gaze of the soul or the heart of man
The word "good" in Greek means "simple, single, uncomplicated"
The word "bad" in Greek means "wicked, evil"
In the Scriptures, the expression "evil eye" is used to mean "envious, covetous" - cf.Pr 23:6;Mt 20:15;Mk 7:22
Explaining the metaphor used by Jesus:
If the heart or gaze of the soul be "good" ("single" in its love for the things of God), then one is filled with "light" (goodness, righteousness, and truth) - cf.Ep 5:8-10
If the heart or gaze of the soul be "evil" (full of envy, covetousness), then one's soul is filled with "darkness" (selfishness, wickedness, and falsehood)!
Thus the need for Jesus' warning:
To guard what goes in your eye
I.e., what you allow your eyes to dwell upon
Remember, there is such a thing as "the lusts of the eyes" (i.e., materialism)
To be rich toward God, free from covetousness -Lk 12:13-21
Have you given much thought as to how you can be rich in good works, ready to give, willing to share? Store up a good foundation for the time to come, and lay hold on eternal life...!