The Book of Virtue, Enjoining Good Manners, and Joining of the Ties of Kinship
حَدَّثَنِي عُبَيْدُ اللَّهِ بْنُ عُمَرَ الْقَوَارِيرِيُّ، حَدَّثَنَا يَزِيدُ بْنُ زُرَيْعٍ، عَنْ عُمَرَ بْنِ مُحَمَّدٍ، عَنْ أَبِيهِ، قَالَ سَمِعْتُ ابْنَ عُمَرَ، يَقُولُ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَا زَالَ جِبْرِيلُ يُوصِينِي بِالْجَارِ حَتَّى ظَنَنْتُ أَنَّهُ سَيُوَرِّثُهُ " .Ibn Umar reported Allah's Messenger (ﷺ) as saying:Gabriel impressed upon me (the kind treatment) towards the neighbour (so much) that I thought as if he would soon confer upon him the (right) of inheritance
From Sahih Muslim, whose reports the scholars accept as authentic.