The secret of prosperity, of course, would be to live within your income, to spend less than what you earn, and not go into debt. That would be the greatest wisdom in a nutshell! If you have not got the cash, then don’t purchase items - go without them.
Yet, there are certain laws of prosperity which stem from eternal spiritual truths. If you begin to feel and think lack (want), you experience lack. If you assert your abundance, then, as the shadow follows the person, abundance follows you.
Desire is poverty. Desire is a feeling of inadequacy. When you begin to desire, you are a beggar already. A millionaire who is always wanting to make another million is really a beggar. A porter who is getting, say, four dollars a day and says, “That is quite enough for me” is greater than a millionaire. For he has not that nagging feeling of lack and the beggarly attitude of desire.
To this end, contentment is the true secret of affirming your abundance. Whatever comes, feel full. Once you have contentment, there is nothing that can make you unhappy. If you don't have contentment, nothing can make you happy. The moment desire arises, just reject it. Then you will begin to experience that the desired object comes by itself to you. This is an eternal law.
So, the inner secret of prosperity is to affirm your plenitude, your abundance. The moment you start affirming it, you will find conditions changing, for your conditions are the product of your own thoughts. The vital factor that goes to make up all your life is your thoughts. They are as tangible and substantial as bricks that pile up to become a great mansion. They can build your whole life. They can create any condition in your life.
Therefore, the secret of prosperity is to affirm your true abundant nature. After all, you are the master of the whole creation, for you are heir to the One who is Master of everything. In truth, you lack nothing. All plenitude, all abundance is our real Self. Your true nature is plenitude. The more you begin to affirm this fact with perfect confidence, not as a thing to be, but as a fact that is, prosperity is yours.
This is a law which has been proved in the life of all those who have discovered and applied it. The more you desire, the more does your want increase. The more you assert your abundance, the more abundance follows you. Let this theorem be in your mind. Let it be in your heart.