Grace is a term used to describe the unmerited favor of God towards mankind. It is God’s kindness towards us, even though we do not deserve it. In other words, grace is God’s love and mercy shown to us even when we have failed to live up to His standards.
Mercy is a term used to describe God’s attitude towards us when we have sinned. It is God’s compassion and forgiveness towards us when we have gone against His commands. Mercy is God’s kindness towards us, even though we have wronged Him.