A generous man will prosper; he who refreshes others will himself be refreshed. Prov. 11:25
There are a number of ways to look at prosperity, but a common thread that runs throughout the Bible is that God's blessing goes beyond material things. From the book of Genesis Abraham was told that he would be blessed in order that he could be a blessing to others (Gen. 12:3), to the end of Revelation (Rev. 22:14), those who stand before God are called a blessed people. This is not measured in bank accounts, accumulation of goods, or if we have the latest gadgets; it's measured in wealth of character, a generous spirit, and an attractive graciousness that cannot be bought or sold.
It must be noted that the principle of "you reap what you sow" (Gal. 6:7-10) is taught in the context of the filling of the Holy Spirit. It is a natural outflow of the fruit of the Spirit in our lives, and not something that is done for reciprocity. The same holds true for this verse in the Proverbs, and for all the teaching associated with God's blessing in the chapters to follow. All that we receive from the Lord is not to be hoarded, but it is given to be shared (Prov. 11:10, 11).