I've heard of the Corporal and Spiritual Works of Mercy. What are they, and what's the difference?
As God has shown us mercy, so too are we called to show mercy to those we encounter. We see mercy throughout the Gospels, but the parable in Matthew 25 forms the foundation for the first set of Works of Mercy. This parable of the last judgment shows each person being asked how well they cared for those around them, and being reminded that this care for those in need is care for God Himself. Each person is asked if they have fed the hungry, given drink to the thirsty, clothed the naked, sheltered the stranger, cared for the sick, and visited the imprisoned. These - along with burying the dead - are the Corporal Works of Mercy, as they primarily concern the physical life of a person.
The list of the Spiritual Works of Mercy developed later. These actions of love primarily concern the inner life of a person. They are instructing the ignorant, counseling the doubtful, admonishing sinners, bearing wrongs patiently, forgiving offenses, comforting the afflicted, and praying for both the living and the dead. All of these actions are concrete ways of bringing the love of God into the world.