Is it permissible for a woman to pray in her nightgown? Thank you very much.

The jurists have agreed that the 'awrah (parts of the body that must be covered) of a woman during prayer is everything except the face and the palms of the hands. They differed regarding the feet. The Malikis, Shafi'is, and Hanbalis held that they are part of the 'awrah, while others maintained that covering them is not obligatory. As for anything beyond that, they agreed on the obligation of covering it and the impermissibility of exposing it.

The jurists adduced as evidence the hadith of Umm Salamah, may Allah be pleased with her, who asked the Prophet, peace and blessings be upon him: "Can a woman pray in a dir‘ (a loose, long dress) and a khimar (head covering) without an izar (a lower garment)?" He replied: "If the dir‘ is ample and covers the tops of her feet."

They also adduced as evidence the hadith of 'A'ishah, may Allah be pleased with her, that the Prophet, peace and blessings be upon him, said: "The prayer of a menstruating woman is not accepted except with a khimar."

As for the ruling on the validity of prayer with the 'awrah uncovered due to forgetfulness, the Malikis held that covering the 'awrah is an obligation, but not a condition [for the validity of prayer]. Thus, the prayer of one who uncovered her 'awrah out of forgetfulness is valid, though she incurs sin. She must repeat the prayer within the prescribed time if she was aware and capable.