How do we know salvation is entirely by God's mercy?

The doctrine of salvation by grace through mercy is central to Reformed theology, emphasizing that God is merciful to those He chooses. In Luke 1:78, it states that salvation comes through the tender mercy of our God. This concept is reiterated in Romans 3:23-24, where it explains that we have all sinned and fall short of God's glory, but we are justified freely by His grace. This underscores that salvation is not something we can earn; it is a gift given by God’s mercy, whereby He withholds the punishment we rightfully deserve. The message is that while we were dead in sin and rebels against God, He graciously extends mercy and saves His people through the finished work of Jesus Christ.