There is the "Peace Prayer" attributed to St. Francis of Assisi. St.Francis was a very interesting monk. After undergoing deep spiritual experiences, he gave away everything he owned and went to help the poor and downtrodden. He lived a very simple life that was dedicated to spreading peace to other people and nature. His life exemplified the path of peace to all creation and the "Peace Prayer" is a dedication to him.
"Lord make me an instrument of your peace.
Where there is hatred,
Let me sow love;
Where there is injury, pardon;
Where there is error, truth;
Where there is doubt, faith;
Where there is despair, hope;
Where there is darkness, light;
And where there is sadness; joy.
O Divine Master grant that I may not so much seek to be consoled as to console.
To be understood, as to understand;
To be loved, as to love.
For it is in giving that we receive,
It is in pardoning that we are pardoned,
And it is indying that we are born to eternal life."