Does Having Murderous Thoughts Without Action Violate the Precepts?

In the Hīnayāna teachings this does not count as violating the precepts: there was no action, the event did not come to completion, no one was killed, so the killing precept is not violated. But in the Mahāyāna it counts as a violation, because the mind is the master of all things and also the master of all evils; only when a mental thought arises will subsequent bodily and verbal actions appear. Only when the mind gives rise to a thought of killing does the karma of killing come into being. Therefore, once a thought of killing arises, one has already violated the precept according to Mahāyāna vinaya, regardless of whether one actually killed or not. The thought plays the decisive role; the thought represents the wholesomeness or unwholesomeness of the mind. When a thought arises, karma arises; karmic retribution manifests according to the mind, and birth and death exist according to the mind. Because as soon as a thought arises—even before action follows—tathāgatagarbha has already made a record, and in the future tathāgatagarbha will actualize the karmic retribution of wholesome or unwholesome deeds according to that record. If action follows as well, the unwholesome karma is further consolidated, and the retribution becomes even more firm. True practitioners do not give rise to thoughts casually; if thoughts arise, they are pure thoughts, thoughts of benefiting sentient beings.

The fundamental reason sentient beings violate the precept against killing lies in the mind of anger (dveṣa) and the mind of competing to win. As long as one subdues the afflictive mind of anger, one will not violate the killing precept. Keep away from people and situations that easily give rise to anger, keep away from competitive, contentious environments, do not contend with people, do not contend with affairs, subdue the self-mind—then basically one will not violate the killing precept.

What deeply taints the mind with anger and malice are various forms of entertainment and games, in which wars and combat are simulated, all involving fighting and killing, bloodshed and violence. People immersed in such games severely pollute their own minds; steeped in these defilements, they unknowingly come to accept bloodshed and violence, considering fighting and killing to be normal. In the future, when they encounter adverse conditions in real life, they will easily give rise to a combative mind and may even commit violence.

In the precept sūtras the Buddha said that even an imagined killing, with no real person and no real event, still counts as a violation of the precept, because the mental thought was stirred and the mental action arose; the seed of unwholesome karma has been stored, and when conditions ripen, there will be unwholesome retribution. The mental thought determines everything. Only by removing all evil and unwholesome thoughts and being replete with wholesome thoughts will one not violate the precepts and create unwholesome karma, will not have the unwholesome retribution of the three evil destinies, will not have unwholesome retribution among humans, and will gradually be able to realize the fruits and escape the birth-and-death cycle of the six destinies.