Sahih Muslim 45 b
It is narrated on the authority of Anas that the Prophet (may peace blessings be upon him) observed:
By Him in whose Hand is my life, no, bondsman (truly) believes till he likes for his neighbour, or he (the Holy Prophet) said: for his brother, whatever he likes for himself.
وَحَدَّثَنِي زُهَيْرُ بْنُ حَرْبٍ، حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، عَنْ حُسَيْنٍ الْمُعَلِّمِ، عَنْ قَتَادَةَ، عَنْ أَنَسٍ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏
"‏ وَالَّذِي نَفْسِي بِيَدِهِ لاَ يُؤْمِنُ عَبْدٌ حَتَّى يُحِبَّ لِجَارِهِ - أَوْ قَالَ لأَخِيهِ - مَا يُحِبُّ لِنَفْسِهِ ‏"‏ ‏.‏