From the Mahasaccaka Sutta,
The Greater Discourse to Saccaka
The Buddha said, “Could there be another path to enlightenment?” And then he considered: “I recall that when my father the Sakyan was occupied, while I was sitting in the cool shade of a rose-apple tree, quite secluded from sensual pleasures, secluded from unwholesome states, I entered upon and abided in the first jhana, which is accompanied by applied and sustained thought, with rapture and pleasure born of seclusion. Could that be the path to enlightenment? Then, following on that memory, came the realization: ‘That is indeed the path to enlightenment.’ I thought: ‘Why am I afraid of that pleasure that has nothing to do with sensual pleasures and unwholesome states?’ I thought, ‘I am not afraid of that pleasure since it has nothing to do with sensual pleasures and unwholesome states.’”
In the Mountains and Rivers Order, we celebrate the enlightenment of Shakyamuni Buddha in a very personal way—by seeking to verify his enlightenment experience for ourselves. Through our own practice, we see that complete, unadulterated enlightenment is possible, that the Buddha’s experience 2500 years ago is applicable to you, to me, to every being on this planet, in this universe, emerging anywhere within space and time. As much as we celebrate the enlightenment of the Buddha, we can’t separate it from the flesh and blood experience of Shakyamuni’s own life.