Sahih al-Bukhari Book 78, Hadith 46
Allah' Apostle said, Gabriel kept on recommending me about treating the neighbors in a kind and
polite manner, so much so that I thought that he would order (me) to make them (my) heirs."
The Prophet (ﷺ) said "Gabriel continued to recommend me about treating the neighbors Kindly and politely so much so that I thought he would order me to make them as my heirs.
The Prophet (ﷺ) said, "By Allah, he does not believe! By Allah, he does not believe! By Allah, he does not believe!" It was said, "Who is that, O Allah's Messenger (ﷺ)?" He said, "That person whose neighbor does not feel safe from his evil."