"Beloved, I wish above all things that thou mayest prosper and be in health, even as thy soul prospereth." (3 John 2)
I looked closely at the verb forms in this verse.
The first mention of prosper refers to material and outer gain, because the other mention of prosper speaks of the soul, or the inner part of man: mind, will, emotions.
As one motivational speaker explained, becoming must precede getting of any kind.
We need to know who we are in Christ, that in Him all our sins have been put away forever, and that nothing else is required on our part in order to be justified before Him.
Now, the second verb "be in health" is active, "have health" or even "live healthy" are the best translations one can offer for this interesting statement. We are not healthy in passivity, anyway, but we demonstrate this health in receiving His life in us.
Now, material prosperity and health are dependent on soul prosperity.
How do we get soul prosperity? By walking in the truth of the Gospel, that all our sins are forgiven.
Honestly, that sounds like a pretty simple thing to do, doesn't it?
In reality, there are part of our lives, and memories in our past of fears of the future, which suggest that God's grace is not a limited subject, but a vast, expansive gift, like a treasure of old and new, which we have so much to learn about.
The more that we understand how forgiven we are, the less striving we do in our own efforts, and the more that we permit His life to live through us.
For the record, John was writing to his beloved friend Gaius, and he signals that Gaius' soul was already prospering. As we rest in the truth of God's Word about His righteousness, His life flows all the more freely through us:
"He that believeth on me, as the scripture hath said, out of his belly shall flow rivers of living water." (John 7: 38)
The Spirit of God flowing in and out of us — nothing better defines prosperity inside and outside!