Hadith on Layl: Last third of night best for prayer

Uthman ibn al-‘As reported: The Messenger of Allah, peace and blessings be upon him, said, “A heavenly caller announces every night: Who is supplicating that he may be answered? Who is asking that he may be given? Who is seeking forgiveness that he may be forgiven? It is so until the appearance of dawn.

Source: Musnad Aḥmad 16280

Grade: Sahih li ghayrihi (authentic due to external evidence) according to Al-Arna’ut

عَنْ عُثْمَانَ بْنِ أَبِي الْعَاصِ قَالَ قَالَ رَسُولُ اللهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ ‌يُنَادِي ‌مُنَادٍ ‌كُلَّ ‌لَيْلَةٍ هَلْ مِنْ دَاعٍ فَيُسْتَجَابَ لَهُ هَلْ مِنْ سَائِلٍ فَيُعْطَى هَلْ مِنْ مُسْتَغْفِرٍ فَيُغْفَرَ لَهُ حَتَّى يَنْفَجِرَ الْفَجْرُ

16280 مسند أحمد بن حنبل

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