Narrated ‘Amr bin Ash-Sharid:
Abu Rafi’ sold a house to Sa’d bin Malik for four-hundred Mithqal of gold, and said, “If I had not heard the Prophet saying, ‘The neighbor has more right to be taken care of by his neighbor (than anyone else),’ then I would not have sold it to you.”
Sahih Bukhari, Volume 9, Book86, Number 110