長阿含經 15.p116

15.p116

“Thus, wanderer, as a result of these events, those ascetics and priests say that frivolity is the source of sentient beings. The Buddha thus entirely knows this, and he also knows about what’s beyond it. He knows it but isn’t attached to it. He truly knows suffering and its formation, cessation, enjoyment, danger, and escape. He’s called ‘Tathāgata’ because he was liberated without remainder by his equal observation.”