“But when you give to the poor, do not let your left hand know what your right hand is doing, so that your giving will be in secret; and your Father who sees what is done in secret will reward you” (Matthew 6:3-4).
Federal Visionists love this passage because they think that the Father will reward us when our giving is done in secret. Furthermore, they say that we should think about this reward and use this reward as a motive for giving. However, this contradicts the modern Reformed approach to sanctification.
The Reformed faith has always insisted that our only motivation for obedience is gratitude. Once we are justified by faith alone, then our eternal destinies are secure. Thus, our only possible motive for obedience is gratitude.
If you are obeying with the expectation of some kind of a reward, then you are failing to rest in the finished work of Christ. Rewards are simply Pelagian. Thus, unless you are overflowing with gratitude, you should not obey.
It’s guilt, grace, gratitude. Anything else, and you are not Reformed™.