This is from the fourteen mindfulness trainings from Thich Nhat Hanh, also called Thay. You can see them and more related information on the Deer Park Monastery website.
The Twelfth Mindfulness Training: Reverence for Life
Aware that much suffering is caused by war and conflict, I am determined to cultivate non-violence, understanding and compassion in my daily life, to promote peace education, mindful mediation and reconciliation, within families, communities, nations and in the world. I am determined not to kill and not to let others kill. I will diligently practice deep looking with my Sangha to discover better ways to protect life and prevent war.