Sunan Abi Dawud 1934
سنن أبي داود#1934SahihIbn Mas’ud said “ I never saw the Apostle of Allaah(ﷺ) observe a prayer out of its proper time except(two prayers) at Al Muzdalifah. He combined the sunset and night prayers at Al Muzdalifah and he offered the dawn prayer that day before its proper time
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Zubair Ali ZaiSahih Bukhari (1682) Sahih Muslim (1289)
In-book reference: 11:214