Forgiveness and Union
I've often thought of forgiving as something you do so you're no longer upset or angry at someone. But I think true forgiveness, or perhaps a "fulness" of forgiveness is when your heart opens wide to the person that offended you. Not only is anger at them far from your mind, but love instead starts taking its place. Forgiveness is an act of union, even if it is not reciprocated. To love is to unite with the divine. This, I think, is the main reason Jesus taught that we must pray for our enemies. Not just stop being angry or upset with them, but pray for them, plead to God on their behalf. Not that they might be saved "Like I am saved", but that they may lay down their anger, hurt feelings and unite with divine love "as I hope to," that we all may be partakers of the glory of Life. All Christ was trying to accomplish on the earth was to show through words, symbols, fulfillment of prophecy and sacrifice, is that we should lay down our contentions, lay down our just and unjust claims of retribution and love one another, even giving up our own lives if necessary to obtain this kingdom, or oneness, and by so doing, unite with divine love, by uniting with one another on earth.
"Beloved, let us love one another: for love is of God; and every one that loveth is born of God, and knoweth God. He that loveth not knoweth not God; for God is love...If we love one another, God dwelleth in us, and his love is perfected in us....If a man say, I love God, and hateth his brother, he is a liar: for he that loveth not his brother whom he hath seen, how can he love God whom he hath not seen? And this commandment have we from him, That he who loveth God love his brother also." (1 John 4)