Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
quran:73:6 –

Indeed, the hours of the night are more effective for concurrence ˹of heart and tongue˺ and more suitable for words.  

Assuredly rising in the night, to wake up after ˹having been in˺ sleep, is firmer in tread, ˹more˺ conducive to ˹establishing˺ harmony between the hearing and the heart for the purpose of comprehending the Qur’ān, and more upright in respect to speech, clearer for utterance ˹of devotions˺.
القرآن:٧٣:٦ –

إِنَّ نَاشِئَةَ اللَّيْلِ هِيَ أَشَدُّ وَطْئًا وَأَقْوَمُ قِيلًا  

{إن ناشئة الليل} القيام بعد النوم {هي اشد وطئا} موافقة السمع للقلب على تفهم القرآن {وأقوم قليلا} أبين قولا.