Then come three descriptions of how righteousness abounds in the heart of the hungry. Mercy in verse 7, purity in verse 8 and peacemaking in verse 9. So the answer to the first question is that 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 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. Sometimes it helps get something clear if we can see it over against its opposite.