Musannaf Ibn Abi Shaybah

Hazrat Abu Huraira narrates that the Noble Prophet (peace and blessings be upon him) forbade praying in a single garment in such a way that there is no cloth on the shoulders.

It is narrated similarly through another chain.

Ibrahim Taimi narrates that if one of the companions of the Noble Prophet (peace and blessings be upon him) did not find any sheet or the like to pray in, he would place a rope over his shoulders and perform the prayer.

Ibrahim says that the predecessors considered it disliked to bare the shoulders during prayer.

Hazrat Muhammad bin Ali (may Allah be pleased with him) used to say that a person should cover his shoulders while performing prayer.