The twenty eighth sutta of the Dīgha Nikāya. The Buddha is staying at the Pāvārika ambavana in Nālandā. Sāriputta worships him and declares that there has been, is, and will be, no one greater than the Buddha, or wiser, as regards sambodhi. He admits, in answer to the Buddha, that he knows nothing either of past Buddhas or of future ones, and that he is unable to comprehend the Buddha's mind with his own. But he knows the lineage of the Norm (Dhammanvaya), and is able to deduce therefore the qualities of past and future Buddhas.
He then proceeds to recount the qualities and attainments in which the Buddha is unsurpassed and unsurpassable. The Buddha agrees that Sāriputta’s statement are in agreement with the Dhamma. Mahā Udāyī, who is present, declares his amazement that the Buddha, though possessed of such marvellous qualities, should yet be so serene and resigned. The Sutta ends with an exhortation by the Buddha that Sāriputta should often discourse on this topic to men and women that their doubts may be set at rest.
D.iii.99 116.