四分律行事鈔資持記 2.1445

2.1445

掉臂戒。（譏嫌同上。）前却，却即後也。不犯中，餘緣者，或惡獸、或擔刺；舉手遮者，貫上三事。浮渡者，必掉兩臂故。

The precept against swinging the arms. (The censure is as above.) 'Before and behind'—'behind' means to the rear. Among the non-offenses, 'other circumstances' means either vicious beasts or carrying brambles; 'raising the hand to fend them off' applies to the preceding three situations. As for 'crossing by swimming,' one must swing both arms, hence [it is excused].