Nagasena Bhiksu Sutra 2.46
T 1670B Nāgasena Bhikṣu Sūtra
Part 2: Dialogues 2.46. Incomparability of the Buddha
The king asked, “Is the Buddha incomparable?”
Nāgasena replied, “Yes, the Buddha is incomparable.”
“But how do you know that the Buddha is incomparable?”
Nāgasena asked the king, “Would those who have never seen the great ocean, know that the ocean is great? There are five great rivers, and to each of them, there are also five hundred small tributaries. The five great rivers are: (1) the Ganges, (2) the Sindhu, (3) the Sita, (4) the Oxus and (5) the Sarasvati. The waters of these five great rivers flow to the ocean day and night, but the water in the ocean neither increases nor decreases.”
Then Nāgasena asked the king, “Great king, do you know about this?”
“Certainly, I know,” said the king.
“Because those who have attained enlightenment have spoken of the incomparability of the Buddha. So I believe it.” said Nāgasena.