(40) باب اسْتِحْبَابِ التَّبْكِيرِ بِالصُّبْحِ فِي أَوَّلِ وَقْتِهَا وَهُوَ التَّغْلِيسُ وَبَيَانِ قَدْرِ الْقِرَاءَةِ فِيهَا
'A'isha, the wife of the Messenger of Allah (ﷺ), reported:
The believing women observed the morning prayer with the Messenger of Allah (ﷺ) wrapped in their mantles. They then went back to their houses and were unrecognisable, because of the Messenger of Allah's (ﷺ) praying in the darkness before dawn.
Reference: Sahih Muslim 645 b
In-book reference: Book 5, Hadith 294
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1346