I used to call the adhan during the time of the Prophet ﷺ for the dawn prayer, and when I said, "Hayya ala al-falah," I would say, "Prayer is better than sleep, prayer is better than sleep," in the first adhan.
حدثنا عبد الرحمن حدثنا سفيان عن أبي جعفر قال عبد الرحمن ليس هو الفراء عن أبي سلمان
كنت أؤذن في زمن النبي ﷺ في صلاة الصبح فإذا قلت حي على الفلاح قلت الصلاة خير من النوم الصلاة خير من النوم الأذان الأول
Its isnad is sahih. Abu Jafar is Razi, from whom Sufyan bin Uyayna narrates, and he is trustworthy. Abu Sulayman is Khalil bin Abdullah Asri, and he too is trustworthy. The hadith also mentions the narrators' disagreement in wording.