It is recommended to pray Subh early, at the beginning of its time, when it is still dark; and the length of recitation therein
حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ مُعَاذٍ، حَدَّثَنَا أَبِي، حَدَّثَنَا شُعْبَةُ، عَنْ سَيَّارِ بْنِ سَلاَمَةَ، قَالَ سَمِعْتُ أَبَا بَرْزَةَ، يَقُولُ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم لاَ يُبَالِي بَعْضَ تَأْخِيرِ صَلاَةِ الْعِشَاءِ إِلَى نِصْفِ اللَّيْلِ وَكَانَ لاَ يُحِبُّ النَّوْمَ قَبْلَهَا وَلاَ الْحَدِيثَ بَعْدَهَا . قَالَ شُعْبَةُ ثُمَّ لَقِيتُهُ مَرَّةً أُخْرَى فَقَالَ أَوْ ثُلُثِ اللَّيْلِ .
Sayyar b. Salama reported: I heard Abu Barza saying that the Messenger of Allah (ﷺ) did not mind some delay in the 'Isha' prayer even up to midnight and he did not like sleeping before (observing it) and talking after it. Shu'ba said: I again met him (Sayyar b. Salama) for the second time and he said: Even up to the third (part) of the night.