The third and final section of The Heidelberg Catechism, one of the documents that explains our Presbyterian Faith, is all about Thankfulness.
A faithful understanding about Thankfulness begins with this question: Since we are redeemed from our sin and its wretched consequences by grace through Christ without any merit of our own, why must we do good works?
Answer: Because just as Christ has redeemed us with His blood. He also renews us through His Holy Spirit according to His own image, so that with our whole life we may show ourselves grateful to God for His goodness and that He may be glorified through us; and further, so that we ourselves may be assured of our faith by its fruits and by our reverent behavior may win our neighbors to Christ.
Dr. Bill Nisbet