If you hate someone, you cannot have
peace in God. Because He is the one who said: “For if you forgive men
their trespasses, your heavenly Father will also forgive you (Matthew 6,
14).” And if the other person is not making peace with you, you always
keep yourself away from hate, and pray for him honestly and never say a
bad thing to anyone else about him.
St. Maximus the Confessor, Fourth 100 chapters regarding love, Filokalia
Translated by Dr. Nick Stergiou
http://www.orthodoxpath.org/saints-and-elders-counsels/regarding-forgiveness/