Al-Matalib al-'Aliyah 320 — Covering the awrah

It is narrated from Imam Masruq (may Allah have mercy on him) that he was asked how a slave-woman should perform prayer. He said: "She should pray in the same form and dress in which she goes out (when leaving the house)."
Takhrij: This report is narrated in Musannaf Ibn Abi Shaybah (hadith: 6265); however, the narrator in its chain, Mujalid bin Sa'id, is weak (da'if) according to the majority of hadith scholars.