"If anyone says, "I love God," yet hates his brother, he is a liar. For anyone who does not love his brother, whom he has seen, cannot love God, whom he has not seen." - 1 John 4:20

We all have people that we need to forgive. It is impossible not to, simply because every day we find reasons to hold grudges. Reasons to be angry at our family, friends, co-workers, and even that guy who honked at you all the way to work. And if we are not careful, these feelings of anger can grow, and take over our hearts.
If you have ever watched People's Court you’ll find that many times instead of justice, they focus only on revenge, what they feel the other person deserves. One woman summed it up quite nicely, after a nasty law-suit with her "ex-friend," by saying, "No. She doesn't deserve my friendship... she doesn't deserve my love." So many times life-long friends allow themselves to be separated; not over the $300 lawsuit, but by their feelings of anger and hatred.
Some of these very same people also claim to be proud Christians, and yet they have forgotten that we don't deserve God's love. Just like their friend turned his back on them, we have turned our backs on God... many, many, many times. We have allowed our sins to separate us from God, and only by His mercy and His grace were we brought back to Him.
As Christians we cannot let our anger get the better of us, nor can we allow it to grow to hate. We cannot be like the unmerciful servant who refused to forgive his debtors, even though his debt was forgiven. We cannot hate our brother, and claim to love God, because God is Love (1 John 4:16). He tells us that if we love Him, we will obey His commands, and He commands us to love each other (Leviticus 19:18).