Sunan Ibn Majah, Hadith 66 ⓘ
It was narrated from Anas bin Malik that: "The Messenger of Allah said: 'None of you truly believes until he loves for his brother" or he said "for his neighbor, what he loves for himself."
حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، وَمُحَمَّدُ بْنُ الْمُثَنَّى، قَالاَ حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ، حَدَّثَنَا شُعْبَةُ، قَالَ سَمِعْتُ قَتَادَةَ، يُحَدِّثُ عَنْ أَنَسِ بْنِ مَالِكٍ، أَنَّ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ قَالَ " لاَ يُؤْمِنُ أَحَدُكُمْ حَتَّى يُحِبَّ لأَخِيهِ - أَوْ قَالَ لِجَارِهِ - مَا يُحِبُّ لِنَفْسِهِ " .
also referenced under: Book 1, Hadith 69 (In-Book) & Volume 1, Book 1, Hadith 66 (DarusSalam)