God can help soften your heart, especially when your feelings don't allow much room for charity.
Jesus said to his disciples, “I say to you, love your enemies, and pray for those who persecute you” (Matthew 5:44). For many this is a difficult teaching, one that is not easy to incorporate into our lives, especially when our feelings are intense.
Yet as Christians we are called to imitate the example of Jesus, who even forgave those who killed him.
Here is an adapted prayer from the 19th-century book The key of Heaven that can help soften our heart a bit, praying for our “enemies,” asking God to bless them and show them his mercy.
O God, the lover of peace, and preserver of charity, give peace and true charity to all our enemies. Infuse into our hearts an inviolable love of your charity: that such desires as we conceive by your holy inspiration, may by no temptation be ever changed. In particular, look graciously upon (here name those you pray for), for whom we implore your mercy, and grant them health of mind and body, that they may love you with all their strength. Amen.