Grace is getting what you don’t deserve. Mercy is not getting what you do deserve.
At its core, mercy is about forgiveness and with God it endures forever. Why? Because of Jesus, our sacrificial lamb who endured the punishment for all our sin. But he’s not just any sacrificial lamb — many people before Jesus sacrificed all sorts of animals to gain the forgiveness of God. He’s the perfect sacrificial lamb because now there’s no more need for any more sacrifices.
That’s why we have the lambs in red on the shirt, to remember that Jesus and His willingness to die a bloody death on the cross makes peace between us and God now and forever.