I used to call the adhan for the Messenger of Allah ﷺ, and in the first call to the dawn prayer I would say, "Come to success, prayer is better than sleep, prayer is better than sleep, Allah is the greatest, Allah is the greatest, there is no god but Allah."
أخبرنا سويد بن نصر قال أنبأنا عبد الله عن سفيان عن أبي جعفر عن أبي سلمان
كنت أؤذن لرسول الله ﷺ وكنت أقول في أذان الفجر الأول حي على الفلاح الصلاة خير من النوم الصلاة خير من النوم الله أكبر الله أكبر لا إله إلا الله
[Hasan] Ahmad narrated it, 3/408, from the hadith of Sufyan Thawri, through him, and it is in Sunan al-Kubra, hadith 1611. It contains some defects, among them the unknown status of Abu Salman the muezzin, whose name is Ham, as mentioned in Sunan al-Kubra of Baihaqi, 1/422. The hadith has corroborating narrations, among them hadith 634.