《長部》第八經，佛陀與裸形苦行者 Kassapa 的對話；佛陀指出苦行遠比真正的心性調伏容易得多，反成修行障礙；Kassapa 聞已出家，終證阿羅漢果。

The eighth sutta of the Dīghanikāya, a dialogue between the Buddha and the naked ascetic Kassapa in which the Buddha argues that self-mortification is a hindrance to spiritual development, far less demanding than true mastery over the mind; Kassapa entered the Order and became an Arahant.