Sahih Muslim 16
صحيح مسلم#16Sahihوَحَدَّثَنَا سَهْلُ بْنُ عُثْمَانَ الْعَسْكَرِيُّ، حَدَّثَنَا يَحْيَى بْنُ زَكَرِيَّاءَ، حَدَّثَنَا سَعْدُ بْنُ طَارِقٍ، قَالَ حَدَّثَنِي سَعْدُ بْنُ عُبَيْدَةَ السُّلَمِيُّ، عَنِ ابْنِ عُمَرَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " بُنِيَ الإِسْلاَمُ عَلَى خَمْسٍ عَلَى أَنْ يُعْبَدَ اللَّهُ وَيُكْفَرَ بِمَا دُونَهُ وَإِقَامِ الصَّلاَةِ وَإِيتَاءِ الزَّكَاةِ وَحَجِّ الْبَيْتِ وَصَوْمِ رَمَضَانَ " .
It is narrated on the authority of ('Abdullah) son of 'Umar, that the Prophet (may peace of Allah be upon him) said:(The superstructure of) al-Islam is raised on five (pillars), i. e. Allah (alone) should be worshipped, and (all other gods) beside Him should be (categorically) denied. Establishment of prayer, the payment of Zakat, Pilgrimage to the House, and the fast of Ramadan (are the other obligatory acts besides the belief in the oneness of Allah and denial of all other gods)
Scholarly Authentication
The label above is the grade most of these scholars gave, each scholar counted once — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. When they judged only its chain of narrators (“Isnaad”), the label says “Sound chain”. Each scholar's own wording:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
Sahih Muslim 16 is the standard (Abd al-Baqi) number; this narration is #112 in the MuslimGPT index.
In-book reference: 1:20