C.S. Lewis on Rewards
It is God’s perfect plan and will to give a reward to those who faithfully trust and obey Him. And it is not unspiritual to expect and anticipate those rewards, if we do so in a spirit of humility and gratitude-knowing that God’s rewards manifest His grace to the undeserving. We can meet His merciful requirements for rewards, but we can never truly earn them.
The reward that God gives are not ribbons or medals but actually something of himself. C. S. Lewis explained it well:
"We must not be troubled by unbelievers when they say that this promise of reward makes the Christian life a mercenary affair. There are different kinds of reward. There is the reward which has no natural connection with the things you do to earn it, and is quite foreign to the desires that ought to accompany those things. Money is not the natural reward of love; that is why we call a man a mercenary if he marries a woman for the sake of her money. But marriage is the proper reward for a real lover, and he is not mercenary for desiring it.… The proper rewards are not simply tacked on to the activity for which they are given, but are the activity itself in consummation."
(C. S. Lewis, The Weight of Glory and Other Addresses (Grand Rapids, MI: Eerdmans, 1973), p. 2. From a sermon by Matthew Kratz, Pursuing God in Giving, 1/31/2010)