What does Matthew 6:20 mean?

Matthew 6:20 KJV
But lay up for yourselves treasures in heaven, where neither moth nor rust doth corrupt, and where thieves do not break through nor steal:

Matthew 6:20 MKJV
But lay up treasures in Heaven for yourselves, where neither moth nor rust corrupt, and where thieves do not break through nor steal.

Matthew 6:20 NKJV
“but lay up for yourselves treasures in heaven, where neither moth nor rust destroys and where thieves do not break in and steal.

Matthew 6:20 KJV 2000
But lay up for yourselves treasures in heaven, where neither moth nor rust does corrupt, and where thieves do not break through nor steal:

Interlinear KJV

But /de/ lay up /thesaurizo/ for yourselves /humin/ treasures /thesauros/ in /en/ heaven, /ouranos/ where /hopou/ neither /oute/ moth /ses/ nor /oute/ rust /brosis/ doth corrupt, /aphanizo/ and /kai/ where /hopou/ thieves /kleptes/ do /diorusso/ not /ou/ break through /diorusso/ nor /oude/ steal: /klepto/

Albert Barnes’ Commentary

Verse 20. Lay up treasures…in heaven. That is, have provision made for your eternal felicity. Do not exhaust your strength, and spend your days, in providing for the life here, but let your chief anxiety be to be prepared for eternity. There nothing corrupts, nothing terminates, no enemies plunder or destroy. To have treasure in heaven is to possess evidence that its purity and joys will be ours. It is to be heirs of God, and joint-heirs with Christ to an inheritance incorruptible, undefiled, and that fadeth not away. The heart, or affections, will of course be fixed on the treasure. To regulate the heart, it is therefore important that the treasure, or object of attachment, should be right.