An arahant. He was the son of a wealthy brahmin of Sāvatthi, and being convinced of the Buddha's majesty, as seen at the presentation of the Jetavana, he entered the Order. He dwelt in the forest fulfilling his novitiate, and once came to the Buddha to learn of him. The Buddha, seeing Sāriputta near him wrapt in contemplation, uttered a stanza, that to the monk of lofty thoughts and heedful, sorrow comes not (See Dhammapada, 259). The monk learnt this stanza, and returning to the forest, ever and anon reflected on it. He thus came to be called Ekuddāniya. One day he obtained insight and became an arahant. Later, when Ananda asked him to preach a sermon, it was this stanza that he took as his text.
We are told that in the time of Atthadassī Buddha he was a chief of the yakkhas, and when the Buddha died he went about lamenting that he had not made use of his opportunities. A disciple of the Buddha, named Sāgara, meeting him, advised him to make offering to the Buddha's thūpa. In Kassapa's time he was a householder, and heard the Buddha utter the stanza mentioned above. He entered the Order, and for twenty thousand years practised meditation, repeating the stanza, but gained no attainment (ThagA.i.153f; Thag.v.68).
It is said (DhA.iii.384f) that on fast-days Ekuddāna, alone in the forest, sounded the call for the deities of the forest to attend the preaching of the Law, and uttered his stanza, whereupon the deities made loud applause. One fast-day two monks, versed in the Tipitaka, visited Ekuddāna with a retinue of five hundred each. Seeing them, Ekuddāna's heart was glad and he said: "Today we will listen to the Law." On being asked for an explanation, he described how, when the Dhamma was expounded, the forest grove was filled with the applause of devas. Thereupon one of the Elders recited the Dhamma and the other expounded it, but there was no sound. In order to dispel their doubts, Ekuddāna took his seat and pronounced his one stanza. The sound of the plaudits of the devas filled the forest. The Elders were greatly offended at the conduct of the devas and complained to the Buddha. The Buddha explained to them that the important thing was not the amount of knowledge but the quality of the understanding.
It is noteworthy that the verse, attributed above to Ekuddāniya, occurs in the Vinaya (Vin.iv.54) as having been constantly used by Cūlapanthaka. Whenever it was his turn to preach to the nuns at Sāvatthi they expected no effective lesson, since he always repeated the same stanza, namely, that which is above attributed to Ekuddāniya. The thera, bearing of their remarks, forthwith gives an exhibition of his iddhi-power and of his knowledge of the Dhamma, thereby winning their tribute of admiration.