It was narrated that ‘Ali said:”The Messenger of Allah (ﷺ) 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 ” .
Reference : Sunan Ibn Majah 81
English translation : Vol. 1, Book 1, Hadith 81
Arabic reference : Introduction, Hadith 81