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.
quran:51:18

And in the hours before dawn they would ask forgiveness,  

and at dawns they used to seek forgiveness: they used say, ‘Our Lord! Forgive us’,
القرآن:٥١:١٨

وَبِالْأَسْحَارِ هُمْ يَسْتَغْفِرُونَ  

{وبالأسحار هم يستغفرون} يقولون: اللهم اغفر لنا.

See similar narrations below:

Collected by Dārimī
darimi:1152ʿAbdullāh b. Muḥammad > Ḥafṣ b. Ghiyāth > al-Aʿmash > al-Ḥakam > Miqsam > Ibn ʿAbbās > Suʾil > al--Adhī Yaʾtī Āmraʾatah And Hī Ḥāʾiḍ > Yataṣaddaq Bidīnār or Biniṣf Dīnār

[Machine] Ibrahim said, "He seeks forgiveness from Allah."  

الدارمي:١١٥٢أَخْبَرَنَا عَبْدُ اللَّهِ بْنُ مُحَمَّدٍ حَدَّثَنَا حَفْصُ بْنُ غِيَاثٍ عَنِ الْأَعْمَشِ عَنِ الْحَكَمِ عَنْ مِقْسَمٍ عَنِ ابْنِ عَبَّاسٍ أَنَّهُ سُئِلَ عَنِ الَّذِي يَأْتِي امْرَأَتَهُ وَهِيَ حَائِضٌ قَالَ «يَتَصَدَّقُ بِدِينَارٍ أَوْ بِنِصْفِ دِينَارٍ»

وقالَ إِبْرَاهِيمُ «يَسْتَغْفِرُ اللَّهَ»