From the Five Nikayas (which recorded the words of the Buddha), we find that the Buddha praised noble warriors, warrior elephants, and thoroughbred horses in a few suttas. One of the famous lay disciples was General Siha.
https://www.accesstoinsight.org/tipitaka/an/an05/an05.034.than.html
The Buddha also had a few lay devotees who were kings of various states. Not all Buddhists are monks; in fact, the majority are lay followers. There are no rules which prohibit monks to practice martial arts, although the Buddha also didn’t encourage monks to practice it. For lay followers, there is in essence no prohibition at all. The Five Precepts of no killing, no stealing, no sexual misconduct, no intoxication, no wrong speech (such as lying, malicious or divisive speech, coarse words, idle gossip) are prescribed for Buddhists to practice and cultivate their virtue, for the benefits of themselves. Lay Buddhists who break the precepts are not expelled from the religion; in fact, there is no authority which has any power to regulate the moral conducts of lay followers. Monks who break serious monastic rules may be expelled from a Sangha but they can still be lay Buddhists. In fact, anybody can declare himself/herself as a Buddhist without any formal ritual or ceremony. “All Beings are owners of their Karma. Whatever volitional actions they do, good or evil, of those they shall become the heir.” Unwholesome karma or immoral action from breaking the precepts may result in unwholesome fruition. However, one may do more wholesome karma or moral action through charitable deeds (in terms of material, words, or physical work) and self-cultivation (in terms of virtue, equanimity and wisdom through abandonment of greed, hatred and delusion) to “dilute” the effects of prior unwholesome karma. Loving kindness, compassion and forgiveness, pleasant abiding, and equanimity are the Four Brahmavihara encouraged by the Buddha.
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The Buddha encouraged wholesome deeds which benefit oneself and others. Protecting and defending oneself and the people against external aggression is a wholesome deed. Lay Buddhists should be encouraged to practice martial arts. Monks can opt to learn martial arts too. To cross the flood of suffering, Buddhists are taught to contemplate suffering, impermanence, and non-self; the three marks of existence. An Arahant is an Enlightened monk who has no self; therefore, he will have no fear of losing anything, including his body. It is a gradual process of cultivation. A monk must not desire for sensual pleasure, existence, as well as non-existence. He must walk the middle path, not longing for life but also not longing for death. He must look after his body so that he has the energy and time to cultivate himself in terms of virtue, equanimity and wisdom in order to attain Nibbana or Enlightenment. Practicing martial arts for self defense may be necessary in certain living environments, especially where there are wild animals or barbaric humans. Defending other people from danger is also a good way to practice loving kindness and compassion. It doesn’t have to involve killing of living beings, although it may sometimes be unavoidable. Doing wholesome karma or moral action may reduce the effects of unwholesome karma. If a monk could not attain Arahanthood in this life due to his karma, he can continue his self-cultivation in the next life. Upon his death, he will be an adult again after 18 years. 十八年后又是一条好汉。
RESILIENT KID 