I have heard that on one occasion the Blessed One was staying near Savatthi, in Jeta's Grove, Anathapindika's monastery. Now at that time the Blessed One was instructing urging, rousing, and encouraging the monks with Dhamma-talk concerned with Unbinding. The monks — receptive, attentive, focusing their entire awareness, lending ear — listened to the Dhamma.
Then, on realizing the significance of that, the Blessed One on that occasion exclaimed:
There is, monks, an unborn — unbecome — unmade — unfabricated. If there were not that unborn — unbecome — unmade — unfabricated, there would not be the case that emancipation from the born — become — made — fabricated would be discerned. But precisely because there is an unborn — unbecome — unmade — unfabricated, emancipation from the born — become — made — fabricated is discerned.