Its chain is sound.

The dirʿ is a qamīṣ, that is, a long shirt.

Mālik also related in the Muwaṭṭaʾ 1/160—and the same is reported by Ibn Abī Shaybah and al-Bayhaqī 2/233—from ʿUbayd Allāh al-Khawlānī—who had been an orphan in the care of Maymūnah—that Maymūnah used to pray wearing a dirʿ and a khimār, with no izār.

This chain, too, is sound.

There are other reports in this chapter showing that women praying in a dirʿ and a khimār was something well known among them, and that it represents the minimum required of them to cover their private parts during prayer. This does not conflict with what Ibn Abī Shaybah and al-Bayhaqī transmitted from ʿUmar ibn al-Khaṭṭāb, who said: “A woman prays in three garments: a dirʿ, a khimār, and an izār.”

Its chain is sound.

In another route, Ibn ʿUmar said:

“When a woman prays, let her pray in all her clothes: the dirʿ, the khimār, and the milḥafah.”

Ibn Abī Shaybah recorded it, and its chain is also sound.

All of this is to be understood as what is more complete and preferable for her. Allah knows best.

Under the heading “What clothing is obligatory and what is recommended,” he says: “And from Buraydah: the Messenger of Allah ﷺ forbade a man to pray in … trousers when he has no cloak upon him. Narrated by Abū Dāwūd and al-Bayhaqī.”

I say: Its chain is ḥasan, as I have demonstrated in Ṣaḥīḥ Abī Dāwūd, 646.