1 Corinthians 3:14

If any man's work abide which he hath built thereupon, he shall receive a reward (KJV)

Then: Paul closes out the foundation metaphor with a hope and a promise. Any work of the builders which survives the fire qualifies the worker for a reward. That had to encourage the Corinthians. Of course, as previously noted, the foundation will stand. Even if they were misled by itinerant teachers and spent time doing work with no value, they will still have Christ's forgiveness and eternal life. Morris (p. 66) clarifies that the fire which all endure is not for the purpose of purifying, but only for testing. On it's basis, none will be excluded from eternity, but work accomplished is measured.

Now: Paul doesn't describe what a heavenly reward is. It has to be above and beyond believers' hope of living in the presence of Christ is. It might rest with appointment to positions of authority in the kingdom of God. It might mean where one gets to be seated in heaven; however, in heaven the limitations of physical existence, close and far, no longer apply. There is just no way for us to understand "reward" in the here and now.

Extra source: The First epistle of Paul to the Corinthians: an introduction and commentary by Leon Morris (Grand Rapids MI: Wm B. Eerdmans, c1985, 2002) online at http://books.google.com/books?id=lNc0AYIqQvAC&dq=Corinthians+Morris&printsec=frontcover&source=bl&ots=NwNTeWfd4I&sig=XgqcdeZIJ7jIfOrxTT7PUqQqo_4&hl=en&ei=F-MkS82TPIvWlAfW55D-CQ&sa=X&oi=book_result&ct=result&resnum=2&ved=0CAwQ6AEwATgK#v=onepage&q=&f=false