(48) باب اسْتِحْبَابِ زِيَادَةِ التَّغْلِيسِ بِصَلاَةِ الصُّبْحِ يَوْمَ النَّحْرِ بِالْمُزْدَلِفَةِ وَالْمُبَالَغَةِ فِيهِ بَعْدَ تَحَقُّقِ طُلُوعِ الْفَجْرِ
A'bdullah (b. 'Umar) reported:
I have never seen Allah's Messenger, (ﷺ) but observing the prayers at their appointed times except two players, sunset and 'Isha, ' at Muzdalifa (where he deferred the sunset prayer to combine it with 'Isha' and he observed the dawn prayer before its stipulated time on that day (10th of Dhu'l-Hijja).
Reference: Sahih Muslim 1289 a
In-book reference: Book 15, Hadith 320
USC-MSA web (English) reference(deprecated numbering scheme): Book 7, Hadith 2956