Romans 12:19-21 KJV
Dearly beloved, avenge not yourselves, but rather give place unto wrath: for it is written, Vengeance is mine; I will repay, saith the Lord.  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.  Be not overcome of evil, but overcome evil with good.
As the truth settled into my being, Marlene had passed into a new life. Two things occurred with me, first a sense of loss, but it was a sensation that something had been ripped away from my being.
Then the Lord brought this to me. Since men became enemies to God, they have been very ready to be enemies one to another. And those that embrace religion, must expect to meet with enemies in a world whose smiles seldom agree with Christ’s.
Recompense to no man evil for evil. That is a brutish recompense, befitting only animals, which are not conscious of any being above them, or of any existence hereafter. And not only do, but study and take care to do, that which is amiable and creditable, and recommends religion to all with whom you converse.
Study the things that make for peace; if it be possible, without offending God and wounding conscience. Avenge not yourselves. This is a hard lesson to corrupt nature, therefore a remedy against it is added.
Give place unto wrath. When a man’s passion is up, and the stream is strong, let it pass off; lest it be made to rage the more against us. The line of our duty is clearly marked out, and if our enemies are not melted by persevering kindness, we are not to seek vengeance; they will be consumed by the fiery wrath of that God to whom vengeance belongeth.
The last verse suggests what is not easily understood by the world; that in all strife and contention, those that revenge are conquered, and those that forgive are conquerors.
Be not overcome of evil. Learn to defeat ill designs against you, either to change them, or to preserve your own peace. He that has this rule over his spirit, is better than the mighty. God’s children may be asked whether it is not more sweet unto them than all earthly good, that God so enables them by his Spirit, thus to feel and act.
Proverbs 12:13-15 KJV
The wicked is snared by the transgression of his lips: but the just shall come out of trouble.  A man shall be satisfied with good by the fruit of his mouth: and the recompense of a man’s hands shall be rendered unto him.  The way of a fool is right in his own eyes: but he that hearkeneth unto counsel is wise.