The Messenger of Allah ﷺ said, "The first two adversaries to be judged on the Day of Resurrection will be two neighbors."
حدثنا قتيبة حدثنا ابن لهيعة عن أبي عشانة
قال رسول الله ﷺ أول خصمين يوم القيامة جاران
Its isnad is hasan, and it is found in Tabarani in Al-Kabir 17/303 and 309. Haythami said in 10/339, "Ahmad narrated it with a hasan isnad."