《长部》第八经，佛陀与裸形苦行者 Kassapa 的对话；佛陀指出苦行远比真正的心性调伏容易得多，反成修行障碍；Kassapa 闻已出家，终证阿罗汉果。

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.