“On one occasion when he was sitting under a Siṃsapā tree, the Buddha took some of the leaves in his hand and asked his disciples thus, “What do you think, bhikkhus, which is more numerous, these few Siṃsapā leaves that I have taken up in my hand or those in the Siṃsapā grove overhead?” When the disciples answered that there are more leaves in the Siṃsapā grove overhead, Buddha then said, “Similarly, it is definite that there is much more than whatever I have told you.” Further, the Buddha has said that he has not told these things because they are unbeneficial, irrelevent to the fundamentals of the holy life, and do not lead to revulsion, to dispassion, to cessation, to peace, to direct knowledge, to enlightenment, to Nibbāna."
[The Siṃsapā Grove (SN 56:31)]
What the Buddha is interested in teaching us is the knowledge and understanding of suffering and the cessation of suffering. That is all!
There are many stories and similies found in the life of the Buddha and in the Jataka tales that are designed to deliver certain messages. What is illustrated in the story above is trying to tell us this: seek only what is necessary for your own deliverance (realisation).
The Buddha is not putting down other knowledges in the world. He is not prohibiting us to seek them tirelessly too. What he actually means is that there are so many knowledges in the world, and his doctrine is merely meant to help us getting out of samsara! If you are interested in this, then his teachings are for you.
This story is in fact used to handle some metaphysical questions put forward to the Buddha. For example: “Is the whole universe eternal or not eternal?” “Is there an origin and an end to the universe?” “What happened to the Buddha after death?” “Is the body and self the same?”
So to speak, some people became too attached in seeking for the things lying so far away, but in the matter of fact, they have not even learnt how to become a good person in the first place! It is just like trying so hard to find out how many leaves there are in forest, but couldn’t even bother to look at what is there in the leaves of the Buddha’s hand!
My thought: Some people think that the Buddha teaches deep and philosophically profound doctrine, some deep psychological concepts or whatsoever. Some even think that the dependent origination doctrine can lead us to discover the origin of the universe. Some think that the Buddha is a physicist, his doctrine can expose the mystery of quantum physics.
To me, all these are extremely unnecessary and irrelevant. The teachings are expounded so clearly enough, and indeed pointing right to the “moon”: to know the mind, to develop the mind and to free the mind (via mindfulness). That is the most important of all, and I would sincerely think so…