كتاب الْمَسَاجِدِ وَمَوَاضِعِ الصَّلاَةِ
5
The Book of Mosques and Places of Prayer
(41)
Chapter: It is disliked to delay the prayers beyond their proper times, and what a person should do if the Imam delays the prayer
(41)
باب كَرَاهِيَةِ تَأْخِيرِ الصَّلاَةِ عَنْ وَقْتِهَا الْمُخْتَارِ وَمَا يَفْعَلُهُ الْمَأْمُومُ إِذَا أَخَّرَهَا الإِمَامُ

Abu Dharr reported:

My friend (the Holy Prophet) bade me to hear and obey (the ruler) even if he is a slave having his feet and arms cut off, and observe prayer at its prescribed time. (And further said): It you find people having observed the prayer, you in fact saved your prayer, otherwise (if you join with them) that would be a Nafl prayer for you.
وَحَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ إِدْرِيسَ، عَنْ شُعْبَةَ، عَنْ أَبِي عِمْرَانَ، عَنْ عَبْدِ اللَّهِ بْنِ الصَّامِتِ، عَنْ أَبِي ذَرٍّ، قَالَ إِنَّ خَلِيلِي أَوْصَانِي أَنْ أَسْمَعَ وَأُطِيعَ وَإِنْ كَانَ عَبْدًا مُجَدَّعَ الأَطْرَافِ وَأَنْ أُصَلِّيَ الصَّلاَةَ لِوَقْتِهَا ‏ "‏ فَإِنْ أَدْرَكْتَ الْقَوْمَ وَقَدْ صَلَّوْا كُنْتَ قَدْ أَحْرَزْتَ صَلاَتَكَ وَإِلاَّ كَانَتْ لَكَ نَافِلَةً ‏"‏ ‏.‏
Reference : Sahih Muslim 648 c
In-book reference : Book 5, Hadith 303
USC-MSA web (English) reference : Book 4, Hadith 1355
  (deprecated numbering scheme)