佛說處處經 1.15

1.15

"That dust and water do not cling to the inside of the Buddha's kāṣāya, nor does external filth cling to it, is due to two nidānas: first, because he does not dwell upon any person's evil; second, because seeing that all people have desires, he wishes to extinguish them. That the Buddha nevertheless washes his kāṣāya is because external filth does not cling to it, but internal filth clings, for where there is a body there is filth. Why is this? External practices have already been exhausted, so filth does not cling externally; internal practices are not yet exhausted, so filth clings to it. Because having a body means the internal is not yet exhausted, and because he takes having a body to be a fault, he does not begrudge his body or life. Why then does he nevertheless cherish his life? Because he uses life to attain the Way.