梵網經菩薩戒本疏 6.155

6.155

七、通塞者，病若新差無力，若自闇鈍，若彼非實求，若外道詐來，若具遮難，一切不犯。反上皆犯。

Seventh, permissibility and prohibition: If one is ill, newly recovered and lacking strength, if one is dull-witted oneself, if the other is not truly seeking, if a tīrthika comes deceitfully, or if they possess the obstacles, in all such cases there is no offense. Contrary to the above, all are offenses.