四分律行事鈔資持記 2.1158

2.1158

次科，《僧祇》，初明洗鉢。不摩拭者，恐損色故。當護下，明護手。捉袈裟者，容有塵污，故須更洗。（舊云因明著袈裟須淨手者，非。）

The next subsection: the Mahāsāṃghika-vinaya first clarifies washing the bowl. Not rubbing or wiping it is for fear of damaging its color. Below, from "Should guard", it clarifies guarding the hands. As for grasping the kāṣāya, there could be dust and defilement, so one must wash again. (The old explanation saying that this clarifies needing to purify hands before donning a kāṣāya is incorrect.)