四分戒本疏卷第一．第二．第三 2.76

2.76

販賣戒第二十　制意者。凡出家之人理息緣務靜坐修道。何得利自販博馳騁市肆。動越威儀。招世譏醜。財物既交或容犯重。臨危險行非高節。以斯諸過聖不許。多論四義故佛制此戒。一為佛法僧上故。二為止鬪諍故。三為成聖種故。四為長信敬不誹謗故　別緣有六。一在家。二眾外道亦攝三共相貿易。三決價四為己。五自貿易。六領受即犯。已下正明戒本。此因跋難陀以生薑易食故起過。又共外道博衣悔而不得。遂譏嫌。佛便制戒。

The twentieth precept: Commercial trading. Regarding the intention behind the prohibition: In general, renunciant persons should, in principle, cease practical affairs and sit in quietude to practice the Path. How could they, for profit, engage in personal trading and gallop through marketplaces, upsetting and violating proper deportment and incurring the ridicule and ugliness of the world? When material wealth changes hands, one might even commit a grave offense; walking on the verge of danger is not a noble conduct. Due to all these faults, the holy one did not permit it. According to the Sarvāstivāda-vinaya-vibhāṣā, there are four reasons the Buddha instituted this precept: 1. to show the supremacy of the Buddha, Dharma, and Saṃgha; 2. to stop disputes and quarrels; 3. to bring about the holy lineage; 4. to increase faith and reverence and prevent slander. The particular conditions are six: 1. laypeople, 2. the twofold assembly [of non-monastics], with non-Buddhists also included, 3. trading together with each other, 4. fixing a price, 5. for oneself, 6. trading personally, 7. receiving it immediately constitutes an offense. Below, the text of the precept is properly explained. This arose from Upananda's fault of exchanging fresh ginger for food. Furthermore, he bartered robes with non-Buddhists, regretted it, and could not retrieve them, whereupon criticism arose, and the Buddha established the precept.