NIV version says:
The plans of the diligent lead to profit as surely as haste leads to poverty. (Tell that to your kids and they will gloss over with boredom)
CEV version (aka: kid friendly version) says:
If you plan and work hard,
you will have plenty;
if you get in a hurry,
you will end up poor.
You can tell your kids to plan as well as work hard, but having the bible to back you up will probably go further. When you crack open the good book, it's amazing how much good instruction is given to us by God about our finances. Making sure the kids understand the biblical standpoint on financial management is essential to their future success.
How can they be diligent?
"Spend some, save some, give some" strategy is a great start. Teach them when they receive money to make a plan for their money, not just spend every dime. Try encouraging your sprouts to save a little and give a little, but do so as it is age appropriate. At the very least, try to slow them down to keep them from running straight to the store with their fresh dollar(s) burning a hole in their pocket.
Teach them good work ethic. It's one thing when they are little and will inevitably make a bigger mess than they are help, but at least they are helping. My kids are great helpers and I believe it's because even when it killed me to let them do a job, I smiled and praised them. I didn't go back and redo the job until they were in bed, blissfully unaware. As your children get older, work as a team and show them HOW to do things properly. Then, after enough instruction and maturity has occurred, push for diligence in the work they do.
Encourage perseverance. There is always a fine balance between keeping our kids from giving up too easily and allowing them to become overwhelmed or frustrated. For example, one rule we generally have is that if you sign up for a sport, you play it for the whole season. I never make them sign up, so it's their choice and they know they have to finish the season. They don't ever have to sign up again, but they have to stick it out for the time signed up for. Only once we let our son out of it, but that was because the coach wasn't showing up, telling us when games were or doing anything at all (there can be exceptions to any rule).
Reward hard work. We don't want our kids to expect something every time they do what they are supposed to do. However, when one of our kids does something unexpected or exceptionally well, we at the very least praise them. Depending on the level of good work, we might do more. We might have a mini-celebration, go to a restaurant, go to a movie, have a Popsicle or any other creative way to honor that effort. We celebrate and reward hard work as often as we possibly can so that they can see diligence leads to good things.