釋禪波羅蜜次第法門 2.16

2.16

6. Obtaining the precepts through doctrinal debate: this refers to the novice Sudaya debating doctrine with the Buddha. The Buddha questioned him on the meaning of impermanence and so forth, and he was able to answer every point. Later the Buddha asked, "Where is your home?" He answered the Buddha, saying, "The three realms are all empty; why does the World-Honoured One ask where my home is?" The Buddha said to Ānanda, "Take him back among the saṅgha to confer the full ordination on him." At that time he was only seven years of age.