إِنَّ نَاشِئَةَ ٱلَّيۡلِ هِيَ أَشَدُّ وَطۡـٔٗا وَأَقۡوَمُ قِيلًا ٦
Indeed, the hours of the night are more effective for concurrence [of heart and tongue]1 and more suitable for words.2
Translation: Saheeh International (English)
1 Another accepted interpretation of the same words is "Indeed, arising at night is more difficult...," meaning that it will only be done by sincere believers and not others.
2 i.e., for recitation of the Qur’ān and for hearing and understanding it.