Proverbs 25:21 If thine enemy be hungry, give him bread to eat; and if he be thirsty, give him water to drink:
22 For thou shalt heap coals of fire upon his head, and the LORD shall reward thee.
These verses are familiar to some us and they simply say what Jesus told us to do and that is not only to do good deeds for your enemies but also pray for them. The scriptures also tell us that vengeance is mine thus saith the Lord. When we do good continually for our enemies it will cause them to have a repentant attitude and want to ask forgiveness. As the last verse says it like heaping coals of fire on their heads when we do good for them but it is actually causing them to see the error in what they did. This is sometimes hard to do but we should strive to always treat our enemies with the love of Christ, just like He did when He said on the cross Father forgive them for they know not what they do.