Sunan an-Nasa'i · Hadith 648
The Book of the Adhan (The Call to Prayer) - كتاب الأذان
أخبرنا إسحاق بن إبراهيم، قال أنبأنا المعتمر بن سليمان، عن أبيه، عن أبي عثمان، عن ابن مسعود، عن النبي صلى الله عليه وسلم قال " إن بلالا يؤذن بليل ليوقظ نائمكم وليرجع قائمكم وليس أن يقول هكذا " . يعني في الصبح .
It was narrated from Ibn Mas'ud that the Prophet (ﷺ) said: "Bilal calls the Adhan during the night to wake those who are sleeping and so that those who are praying Qiyam can return.[1] Not to say it is like this." The break of dawn is not like this. [2][1] Meaning to finish. Ash-Shawkani said: "To return to sleeping or return to sitting from praying" Nail Al-Awtar.[2] Indicating with an up and down motion. The true dawn is from right to left.
Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).