Therefore if thine enemy hunger, feed him; if he thirst, give him drink: for in so doing thou shalt heap coals of fire on his head.--Romans 12:20
I read a great homily on the above passage at Logismoi. He takes the passage and tells you to look at it from the perspective of Christ's Earthly Ministry. He gave us His Body and Blood for our hunger and thirst. This was meant not as a revenge, but a loving offering that our souls would be overcome with His love. The "coals of fire on his head" are meant not as vengeance (vengeance is the Lord's) but rather to stir the soul to repentance and love. In much the same way that Christ's selfless torment on the cross (the word excruciating comes from Latin meaning "of the cross") has brought many souls to repentance.
Please read the homily I linked to above. He says it more eloquently and goes into more detail.
May God bless all who read my ramblings,
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