1. Udāyī Thera.-Also called Lāludāyī (and Pandita Udāyī), to distinguish him from others. - He was the son of a brahmin of Kapilavatthu. He saw the power and majesty of the Buddha when the latter visited his kinsmen and, entering the Order, in due course became an arahant. When the Buddha preached the Nāgopama Sutta (see A.iii.344f), on the occasion when Seta, King Pasenadi's elephant, was publicly admired, Udāyī was stirred to enthusiasm by thoughts of the Buddha and uttered sixteen verses, extolling the virtues of the Buddha, comparing him to a great and wondrous elephant. (Thag.vv.689-704; ThagA.ii.7f.; Udāyī's verses are repeated in the Anguttara (iii.346-7) but the Commentary (ii.669) attributes them to Kāludāyī).
Once when Udāyī was staying at Kāmandā, in Todeyya's mango-grove, he converted a pupil of a brahmin of the Verahaccāni clan and, as a result, was invited by Verahaccāni herself to her house. It was only on his third visit to Verahaccāni that Udāyī preached to her and she thereupon became a follower of the Faith (S.iv.121-4).
The Samyutta Nikāya (iv.166f.; another discussion with Ananda is mentioned in A.iv.426f) also records a conversation between Udāyī and Ananda, when Udāyī asks if it is possible to describe the consciousness, too, as being without the self. On another occasion Udāyī has a discussion with Pańcakanga on vedanā (M.i.396ff; S.iv.223-4; the Commentary SA.iii.86 and MA.ii.629 here describes Udāyī as "Pandita"). Ananda overhears their conversation and reports it to the Buddha, who says that Udāyī's explanation is true, though not accepted by Pańcakanga.
Elsewhere (S.v.86ff) Udāyī is mentioned as asking the Buddha to instruct him on the bojjhangas, and once, at Desaka (Setaka?) in the Sumbha country, he tells the Buddha how he cultivated the bojjhangas and thereby attained to final emancipation (S.v.89).
He is rebuked by the Buddha for his sarcastic remark to Ananda, that Ananda had failed to benefit by his close association with the Master. The Buddha assures him that Ananda will, in that very life, become an arahant (A.i.228).
Udāyī was evidently a clever and attractive preacher, for he is mentioned as having addressed large crowds, a task demanding great powers, as the Buddha himself says when this news of Udāyī is reported to him (A.iii.184).
According to Buddhaghosa (DA.iii.903), it is this same Udāyī (Mahā Udāyī) who, having listened to the Sampasādaniya Sutta, is beside himself with joy at the contemplation of the wonderful qualities as set forth in that Sutta, and marvels that the Buddha does not go about proclaiming them.
Buddhaghosa (MA.i.526) seems to identify him also with the Udāyī to whom the Latukikopama Sutta (M.i.447ff) was preached.
2. Udāyī.-A Thera. It was once his turn to recite the Pātimokkha before the Sangha, but because he had a crow's voice (kākasaraka), he had to obtain permission to make a special effort so that his recitation might be audible to the others (Vin.i.115). It is, perhaps, this same monk who is mentioned in the Vinaya as having been guilty of numerous Sanghādisesa offences (Vin.iii.110f, 119f, 127f, 137f, 135ff).
He is censured again and again and various penalties are inflicted on him, nevertheless he repeats his offences (Vin.ii.38ff). In the Nissagyiya (Vin.iii.205f) a story is told of a nun, a former mistress of Udāyī, who conceived a child through touching a garment worn by him. Once when Uppalavannā asked him to take some meat to the Buddha, he demanded her inner robe as his fees (Vin.iii.208). He seems to have been very fond of the company of women and they returned his liking. (See, e.g., Vin.iv.20, 61, 68). There was evidently a strain of cruelty in him, for we are told of his shooting crows and spitting them with their heads cut off (Vin.iv.124). He is described as being fat (Vin.iv.171). He is perhaps to be identified with Lāludāyī.
3. Udāyī.-A brahmin. He visited the Buddha at Sāvatthi and asked if the Buddha ever praised sacrifice. The Buddha's answer was that he did not commend sacrifices which involved butchery, but praised those which were innocent of any killing (A.ii.43f).
4. Udāyī.-See also under Kāludāyī, Lāludāyī and Sakuludāyī. As they are all, from time to time, referred to as Udāyī it is not always possible to ascertain which is meant. The Commentary is not an infallible guide.