Here is John Davenant’s explanation of how Christians should view rewards. This can be found in his commentary on Colossians.

We conclude, therefore, that a reward to good works is proposed by God, and that it ought to be regarded by us,

1. That hence we may learn the will and munificence [generosity] of God.
2. That we may exercise hope and faith by fixing our view upon it.
3. That hence we may be excited to cheerfulness in good works.

But we ought not to regard and look to the reward;

1. So as to be unwilling to serve God if there is no reward.
2. So as to set the blessedness itself as our end in loving God.
3. So as to infer any merit in our good works from the reward being proposed.

A couple of notes on this.

It is wonderful that Davenant’s first point is rewards point us to God’s generosity and desire for us His people. Rewards are proof that God is a generous, giving God, the overflowing fountain of all good.  Rewards first cause us to praise God and not to praise our virtue.

And of course rewards should motivate us to cheerfully and hopefully work. Too often Christians question of the value of focusing on rewards as we labor for Christ. But Christ promises rewards for those who work and strive. The Scriptures teach this from start to finish. Rewards should drive us to persevere in good deeds.

But Davenant also warns against some dangers with the focus on rewards. Most obvious is the last one, where our works  become a foundation for our salvation. The more works we do the more saved we are. This is explicitly taught in the Roman Catholic system, but it is easy for Protestants to buy into it as well.

The next danger, working up the list, is that rewards become the end instead of God Himself. The goal is always and forever commune with the Lord. Rewards are a byproduct of that goal, but not the ultimate goal.

Finally, there is the danger of refusing to work unless we see the reward.

These last two dangers are often seen in an over-realized eschatology where rewards become the end and those rewards are to be found in this life.  Many health and wealth teacher make the basic error of trying to make the not yet into the already by saying that God rewards us here and now. God does reward us at times in this life. But the great, lasting, and perfect rewards will only be found in the next life. If we expect to do good deeds here and God to reward us quickly, immediately, and in this life, we will often be disappointed.