Al-Adab Al-Mufrad #109
Neighbours
The Arabic includes the chain of narration (sanad) and the collector's commentary; the English translation shows the Prophet's words only.
حَدَّثَنَا الْحُسَيْنُ بْنُ حُرَيْثٍ، قَالَ: حَدَّثَنَا الْفَضْلُ بْنُ مُوسَى، عَنِ الْوَلِيدِ بْنِ دِينَارٍ، عَنِ الْحَسَنِ، أَنَّهُ سُئِلَ عَنِ الْجَارِ، فَقَالَ: أَرْبَعِينَ دَارًا أَمَامَهُ، وَأَرْبَعِينَ خَلْفَهُ، وَأَرْبَعِينَ عَنْ يَمِينِهِ، وَأَرْبَعِينَ عَنْ يَسَارِهِ.
Al-Hasan was asked about the neighbour and said, "The term 'neighbour'
includes the forty houses in front a person, the forty houses behind him,
the forty houses on his right and the forty houses on his left."
About Al-Adab Al-Mufrad
This hadith is #109 from Al-Adab Al-Mufrad, in the Book of Neighbours.