In fact, I guarantee your investment in this area is one that you'll never want to sell (though I do recommend you give some of it away). And I guarantee that you will still profit from this investment.

In Proverbs 23:23, we're told to "Buy truth, and do not sell it. Get wisdom and instruction and understanding."

This may not seem like an investment strategy. And many will say you can't actually buy truth. But think about it. Most parents save as much as they can to pay for their children's college education. Some spend a fortune on private school. And others amass huge libraries in their pursuit of knowledge.

In today's technological world, there is an immense library at your disposal. Just spend some time on the Internet. It contains a wealth of resources. Unfortunately, most people spend their money on entertainment and comfort, rather than on gaining knowledge.

If you think about it, investment is just a fancy word for spending. Only it's not spending money on things you use up (like food and amusement). Instead, you spend money on a house, or a stock, or a mutual fund. And the hope is that you will be able to sell that investment and get your money back plus something extra. It's spending on something that will bring a profit.

The only trouble is you have to sell the investment in order to make money. Knowledge and understanding are investments you never have to sell for them to be profitable. In fact, you have to hold on to them to profit from them!

And if you're looking for a great way to gain knowledge without investing a lot of extra time, buy an mp3 player and listen to it while you drive or exercise. You can download sermons, books, or lectures from the Internet. You can learn a foreign language. Or you can pick up a new skill for a career change or profitable hobby. You'll have to spend some money on the equipment and instruction. But it's an investment that will return exponentially. And you'll never have to sell the knowledge you acquire.