Mercy, not sacrifice

When God asks for a record of your mercy at the judgment day, he will not be asking for a punched time card. You won't say, "Here it is. Eight hours of mercy. Now where's my wage?"
Instead, God will be asking for your medical charts. You will hand them to him in all lowliness and meekness, and there he will read the evidences of how you trusted him as your divine Physician, and how the medicine of his Word and the therapy of his Spirit took effect in your life because you relied on them to heal you of your unmerciful disposition. And when he sees the evidence of your faith and his healing, he will complete your healing and welcome you into the kingdom forever. Therefore, "Blessed are the merciful, for they shall obtain mercy."
- John Piper
The opposite of mercy is religious triviality. How do we know what color of paint Mercy demands ona canvas? We are not required to know what to apply in every situation or have a paint by number diagram, but to be merciful people. Merciful people are broken.

Mercy comes from a heart that has first felt its spiritual bankruptcy, and has come to grief over its sin, and has learned to wait meekly for the timing of the Lord, and to cry out in hunger for the work of his mercy to satisfy us with the righteousness we need.
The mercy that God blesses is itself the blessing of God. It grows up like fruit in a broken heart and a meek spirit and a soul that hungers and thirsts for God to be merciful. Mercy comes from mercy. Our mercy to each other comes from God's mercy to us.
The key to becoming a merciful person is to become a broken person. You get the power to show mercy from the real feeling in your heart that you owe everything you are and have to sheer divine mercy. Therefore, if we want to become merciful people, it is imperative that we cultivate a view of God and ourselves that helps us to say with all our heart that every joy and virtue and distress of our lives is owing to the free and undeserved mercy of God.
-JP... again.