The Diamond Sutra is an ancient Buddhist teaching about how to live a full life. It dates back to the 4th century AD, and it's filled with wise advice about how to be kind to others, be mindful of our thoughts and actions, and be humble. The Diamond Sutra says that true happiness comes from living in a state of "non self", or egolessness, which means accepting that we are all connected and part of the same universe. It also teaches us to be kind to ourselves and others, release judgment and criticism, practice patience, and be present in the moment. In other words, the Diamond Sutra helps us live peacefully and with intention.