إِنَّ نَاشِئَةَ اللَّيْلِ هِيَ أَشَدُّ وَطْءًا وَأَقْوَمُ قِيلًا
[73:6]
Surely the rising by night is the firmest way to tread and the best corrective of speech.
Truly the rising by night is most potent for governing (the soul), and most suitable for (framing) the Word (of Prayer and Praise).
Lo! the vigil of the night is (a time) when impression is more keen and speech more certain.