He gave the call to prayer before dawn, so Umar instructed him, and he mentioned something similar.
حدثنا أيوب بن منصور حدثنا شعيب بن حرب عن عبد العزيز بن أبي رواد أخبرنا نافع
أذن قبل الصبح فأمره عمر فذكر نحوه
No references are available.
[Hasan]. Ibn Abu Shayba (1/222) narrated it from the hadith of Abdul-Aziz bin Abu Rawwad, transmitted through him. Tirmidhi (203) cited it as a suspended chain and said, "This is not sound," and so on. The hadith has corroborating narrations. Saad.