كتاب الصلاة
2  
The Book of Prayer
Bulugh al-Maram 171
Narrated Ibn Mas'ud (RA):
Allah's Messenger (ﷺ) said: "One of the best deeds is to offer Salat (prayer) in its early time." [Reported by at-Tirmidhi and al-Hakim who (both) graded it Sahih].
وَعَنْ اِبْنِ مَسْعُودٍ ‏- رضى الله عنه ‏- قَالَ: قَالَ رَسُولُ اَللَّهِ ‏- صلى الله عليه وسلم ‏-{ أَفْضَلُ اَلْأَعْمَالِ اَلصَّلَاةُ فِي أَوَّلِ وَقْتِهَا } رَوَاهُ اَلتِّرْمِذِيُّ, وَالْحَاكِمُ.‏ وَصَحَّحَاهُ 1‏ .‏
Reference : Bulugh al-Maram 171
In-book reference : Book 2, Hadith 171
English translation : Book 2, Hadith 171
Bulugh al-Maram 171
Its basic meaning is in the Sahihain of al-Bukhari and Muslim.
وَأَصْلُهُ فِي "اَلصَّحِيحَيْنِ" 1‏ .‏
Reference : Bulugh al-Maram 171
In-book reference : Book 2, Hadith 171
Hadith Text
Reference