Thus have I heard:
One time, the Budha was staying at Anaathapindidas Ashrama in Jetavana of Shraavastii.
At that time, Bhagavaan said to the Bhikshus, “In this assembly, I do not see a single practice that, when cultivated and frequently practiced, brings blessings in the human realm, blessings in the heavenly realm, and leads to the realization of Nirvana. What is this practice? It is abstaining from killing.”
Bhagavaan said to the Bhikshus, “If someone does not kill and does not even think of killing, their life will be extremely long. Why is this? Because they do not cause harm. Therefore, Bhikshus, you should learn to abstain from killing. Thus, Bhikshus, you should train yourselves in this way.”
When the bhikshus heard what the Budha said, they followed it with joy.