(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.
Reference: Sahih Muslim 648 c
In-book reference: Book 5, Hadith 303
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1355