(42) بَابُ قَوْلِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «الدِّينُ النَّصِيحَةُ لِلَّهِ وَلِرَسُولِهِ وَلأَئِمَّةِ الْمُسْلِمِينَ وَعَامَّتِهِمْ»
Narrated Jarir bin Abdullah:
I gave the pledge of allegiance to Allah's Messenger (ﷺ) for the following:1. offer prayers perfectly 2. pay the Zakat (obligatory charity)3. and be sincere and true to every Muslim.
Reference: Sahih al-Bukhari 57
In-book reference: Book 2, Hadith 50
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 1, Book 2, Hadith 55