On one occasion the Blessed One was dwelling at Rajagaha in the Bamboo Grove, the Squirrel Sanctuary. There the Blessed One addressed the bhikkhus thus:
“Bhikkhus, once in the past a certain man set out from Rajagaha and went to the Sumagadha Lotus Pond, thinking: ‘I will reflect about the world.’ He then sat down on the bank of the Sumagadha Lotus Pond reflecting about the world. Then, bhikkhus, the man saw a four-division army entering a lotus stalk on the bank of the pond. Having seen this, he thought: ‘I must be mad! I must be insane! I’ve seen something that doesn’t exist in the world.’ The man returned to the city and informed a great crowd of people: ‘I must be mad, sirs! I must be insane! I’ve seen something that doesn’t exist in the world.’
“They said to him: ‘But how is it, good man, that you are mad? How are you insane? And what have you seen that doesn’t exist in the world?’
“‘Here, sirs, I left Rajagaha and approached the Sumagadha Lotus Pond … as above … I saw a four-division army entering a lotus stalk on the bank of the pond. That’s why I’m mad, that’s why I’m insane, and that’s what I’ve seen that doesn’t exist in the world.’
“‘Surely you’re mad, good man! Surely you’re insane! And what you have seen doesn’t exist in the world.’
“Nevertheless, bhikkhus, what that man saw was actually real, not unreal. Once in the past the devas and the asuras were arrayed for battle. In that battle the devas won and the asuras were defeated. In their defeat, the asuras were frightened and entered the asura city through the lotus stalk, to the bewilderment of the devas.
“Therefore, bhikkhus, do not reflect about the world, thinking: ‘The world is eternal’ or ‘The world is not eternal’; or ‘The world is finite’ or ‘The world is infinite’; or ‘The soul and the body are the same’ or ‘The soul is one thing, the body is another’; or ‘The Tathagata exists after death,’ or ‘The Tathagata does not exist after death,’ or ‘The Tathagata both exists and does not exist after death,’ or ‘The Tathagata neither exists nor does not exist after death.’ For what reason? Because, bhikkhus, this reflection is unbeneficial, irrelevant to the fundamentals of the holy life, and does not lead to revulsion, to dispassion, to cessation, to peace, to direct knowledge, to enlightenment, to Nibbāna.
“When you reflect, bhikkhus, you should reflect: ‘This is suffering’; you should reflect: ‘This is the origin of suffering’; you should reflect: ‘This is the cessation of suffering’; you should reflect: ‘This is the way leading to the cessation of suffering.’ For what reason? Because, bhikkhus, this reflection is beneficial, relevant to the fundamentals of the holy life, and leads to revulsion, to dispassion, to cessation, to peace, to direct knowledge, to enlightenment, to Nibbāna.
“Therefore, bhikkhus, an exertion should be made to understand: ‘This is suffering.’… An exertion should be made to understand: ‘This is the way leading to the cessation of suffering.’”