كتاب الصلاة
4  
The Book of Prayers
(28)
Chapter: Straightening The Rows; The Virtue Of The Front Row And Then The Next; Competing With One Another For The Front Row; The People Of Virtue Should Take Precedence And Be Closest To The Imam
(28)
باب تَسْوِيَةِ الصُّفُوفِ وَإِقَامَتِهَا وَفَضْلِ الأَوَّلِ فَالأَوَّلِ مِنْهَا وَالاِزْدِحَامِ عَلَى الصَّفِّ الأَوَّلِ وَالْمُسَابَقَةِ إِلَيْهَا وَتَقْدِيمِ أُولِي الْفَضْلِ وَتَقْرِيبِهِمْ مِنَ الإِمَامِ
Sahih Muslim 437

Abu Huraira reported:

The Messenger of Allah (ﷺ) said: If the people were to know what excellence is there in the Adhan and in the first row, and they could not (get these opportunities) except by drawing lots, they would have definitely done that. And if they were to know what excellence lies in joining the prayer in the first takbir (prayer), they would have vied with one another. And if they were to know what excellence lies in the night prayer and morning prayer, they would have definitely come even if crawling (on their knees).
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ سُمَىٍّ، مَوْلَى أَبِي بَكْرٍ عَنْ أَبِي صَالِحٍ السَّمَّانِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏ "‏ لَوْ يَعْلَمُ النَّاسُ مَا فِي النِّدَاءِ وَالصَّفِّ الأَوَّلِ ثُمَّ لَمْ يَجِدُوا إِلاَّ أَنْ يَسْتَهِمُوا عَلَيْهِ لاَسْتَهَمُوا وَلَوْ يَعْلَمُونَ مَا فِي التَّهْجِيرِ لاَسْتَبَقُوا إِلَيْهِ وَلَوْ يَعْلَمُونَ مَا فِي الْعَتَمَةِ وَالصُّبْحِ لأَتَوْهُمَا وَلَوْ حَبْوًا ‏"‏ ‏.‏
Reference : Sahih Muslim 437
In-book reference : Book 4, Hadith 143
USC-MSA web (English) reference : Book 4, Hadith 877
  (deprecated numbering scheme)