Quick answer
Diligence tends toward freedom and neglect tends toward being directed by someone else. The verse contrasts who ends up holding the schedule.
Read both lines
What the verse compares is not wealth but autonomy. The diligent hand rules, meaning it governs its own affairs, while the alternative is conscripted labor, work you do because someone else says so. That is the same vision of maturity the ant poem held out at 6:7, where the commendable thing was working without a captain or overseer. The proverb is describing a tendency observed over years, and its promise is modest and real: the person who does the work when nobody is watching is generally the person who does not later have to be watched.
What it does not mean
This is not a verse for reading anyone's employment or circumstances as a verdict on their character. Proverbs speaks about the man who will not, and the same book names injustice as a cause of poverty (13:23) and says the LORD takes up the cause of the robbed and afflicted (22:22–23). It is a mirror, not a diagnosis of a neighbor.
Related: Proverbs 6:6–11 · Proverbs 13:23 · Proverbs 22:29
New King James Version®, Copyright © 1982, Thomas Nelson. All rights reserved. Full copyright information. Scripture provided by API.Bible.
Go Deeper
If this verse has been used to put weight on you that it was never carrying, ask about it directly.