The Jataka, Volume I, tr. by Robert Chalmers, , at sacred-texts.com
"With conscious."--This story was told by the Master while at Jetavana, about the interpretation by Sāriputta, Captain of the Faith, at the gate of Saṁkassa town, of a problem tersely propounded by the Master. And the following was the story of the past he then told.
Once on a time when Brahmadatta was reigning in Benares,...&c.... the Bodhisatta, as he expired in his forest-home, exclaimed, "Neither conscious nor unconscious." And the recluses did not believe the interpretation which the Bodhisatta's chief disciple gave of the Master's words. Back came the Bodhisatta from the Radiant Realm, and from mid-air recited this stanza:--
His lesson ended, the Bodhisatta praised his disciple and went back to the Brahma Realm. Then the rest of the recluses believed the chief disciple.
His lesson taught, the Master identified the Birth by saying, "In those days Sāriputta was the chief disciple, and I Mahā-Brahma."