1 John 4:10
This is love: not that we loved God, but that he loved us and sent his Son as an atoning sacrifice for our sins.
Holding a grudge causes stress, causes sleep deprivation, and is a complete waste of energy and your valuable time. You find yourself spending so much time reminding yourself and explaining to others why you feel the way you do. Well God made it simple for us to live in harmony by sacrificing his son for all of our sins, yet, we still feel the need to "get back at people." This is in complete opposition of the greatest commandment, love. Today, when confronted with the desire to hang on to your grudge, remember who loves you first and who paid the ultimate price for you to never worry about the need for holding on to resentment. Then, you will witness love defeat all the stress associated with all that bitterness.