This mention of the word "prosperous" is the first of the only four occurrences of the Greek word enodoo (meaning literally "good journey," but translated "prosper" or "prosperous") in the New Testament. Here it is actually rendered "prosperous journey."
It is obvious that Paul was not praying for his journey to prosper financially, for the next verse indicates his long desire had been to "impart unto you some spiritual gift, to the end ye may be established" (Romans 1:11).
However, the word has come to include any kind of prospering, as in 1 Corinthians 16:2, when Paul urged Christians to provide financial help for other Christians in need. "Upon the first day of the week let every one of you lay by him in store, as God hath prospered him," he said.
The term can also refer to physical and spiritual health. Its two other occurrences are in 3 John 2: "Beloved, I wish above all things that thou mayest prosper and be in health, even as thy soul prospereth." Unfortunately, certain teachers of these latter days have taken the biblical teaching of spiritual prosperity to mean financial prosperity, which they teach is the right of every Christian. But this "prosperity gospel" is so clearly unscriptural that it is merely a testimony to the cupidity of the Christians who believe it. "They that |desire to| be rich fall into temptation and a snare, and into many foolish and hurtful lusts," warned Paul (1 Timothy 6:9). And to whatever extent God does prosper us financially, it is strictly for the purpose of helping others, not to indulge ourselves. "Charge them that are rich in this world, that . . . they do good, that they be rich in good works, ready to distribute" (1 Timothy 6:17-18). HMM