Sunan Abi Dawud — The Rites of Hajj (Kitab Al-Manasik Wa'l-Hajj) — Hadith No: 1938
Translation
Narrated Umar ibn al-Khattab: The Arabs in the pre-Islamic period did not return from al-Muzdalifah till they saw sunlight at the mountain Thabir. The Prophet (ﷺ) opposed them and returned before the sunrise