It is recommended to pray Subh early, at the beginning of its time, when it is still dark; and the length of recitation therein
وَحَدَّثَنِي حَرْمَلَةُ بْنُ يَحْيَى، أَخْبَرَنَا ابْنُ وَهْبٍ، أَخْبَرَنِي يُونُسُ، أَنَّ ابْنَ شِهَابٍ، أَخْبَرَهُ قَالَ أَخْبَرَنِي عُرْوَةُ بْنُ الزُّبَيْرِ، أَنَّ عَائِشَةَ، زَوْجَ النَّبِيِّ صلى الله عليه وسلم قَالَتْ لَقَدْ كَانَ نِسَاءٌ مِنَ الْمُؤْمِنَاتِ يَشْهَدْنَ الْفَجْرَ مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم مُتَلَفِّعَاتٍ بِمُرُوطِهِنَّ ثُمَّ يَنْقَلِبْنَ إِلَى بُيُوتِهِنَّ وَمَا يُعْرَفْنَ مِنْ تَغْلِيسِ رَسُولِ اللَّهِ صلى الله عليه وسلم بِالصَّلاَةِ .
'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.