"I charge you all that each one of you concentrate all the thoughts of your heart on love and unity. When a thought of war comes, oppose it by a stronger thought of peace. A thought of hatred must be destroyed by a more powerful thought of love. Thoughts of war bring destruction to all harmony, well-being, restfulness and content. Thoughts of love are constructive of brotherhood, peace, friendship, and happiness." Abdu'l-Baha, Paris Talks, p. 29,

Whilst looking for the exact words of this quote I came across a lovely page of quotes on peace from all different religions. The page is called Peace Seeds. "[The] site is dedicated to the concept that when one studies different religious traditions, one is struck by the repeated similarities of basic truths." There is no information on who runs the site. There are a number of other categories in which they've gathered like-minded passages from various faiths.