Sunan Ibn Majah, Book 1, Hadith 85 (In-Book) ⓘ
It was narrated that 'Ali said: "The Messenger of Allah said: 'No slave truly believes until he believes in four things: in Allah alone with no partner; that I am the Messenger of Allah; in the resurrection after death; and in the Divine Decree (Qadar).'"
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ عَامِرِ بْنِ زُرَارَةَ، حَدَّثَنَا شَرِيكٌ، عَنْ مَنْصُورٍ، عَنْ رِبْعِيٍّ، عَنْ عَلِيٍّ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " لاَ يُؤْمِنُ عَبْدٌ حَتَّى يُؤْمِنَ بِأَرْبَعٍ بِاللَّهِ وَحْدَهُ لاَ شَرِيكَ لَهُ وَأَنِّي رَسُولُ اللَّهِ وَبِالْبَعْثِ بَعْدَ الْمَوْتِ وَالْقَدَرِ " .
also referenced under: Hadith 81 (Reference) & Volume 1, Book 1, Hadith 81 (DarusSalam)