Thus have I heard.
At one time, when the Buddha was at Savatthi, the monk Malunkyaputta asked "If the Blessed One knows whether the world is eternal, whether the world is finite, whether the life principle and the body are the same, whether an enlightened person continues to exist after death, please teach me about these things."
The Buddha answered "Malunkyaputta, I never said 'Follow me and I will answer your questions' nor did you say 'I will follow the Blessed One because he will explain these matters'.
"Then what is your position? You are like a person shot with a poisoned arrow, who says 'I will not have this arrow removed until I know who shot it, his name, his family, whether he is tall or short, young or old.....' This person would die before all these questions could be answered.
"Malunkyaputta, the religious life does not depend on dogma. Whether the world is eternal or not, whether the world is finite or not, whether the life principle and the body are or are not the same, and whether or not an enlightened person continues to exist after death, there undoubtedly do exist sorrow, discontent, grief and despair, the overcoming of which I make known.
"Why then have I not answered your questions? Because they are not profitable, do not concern religious practice, and do not lead to Enlightenment."