The Messenger of Allah ﷺ said, "Jibreel kept urging me to treat the neighbor well until I thought he would make him an heir."
قال رسول الله ﷺ: مازال جبريل يوصيني بالجار حتى ظننت أنه سيورثه.
It was narrated by Ibn Majah (3674) and Ahmad (8046, 9746), both through various routes from Yunus bin Abu Ishaq, from Mujahid, from Abu Hurairah, and he mentioned it. Its chain is hasan because of Yunus bin Abu Ishaq, for he is hasan al-hadith.It was also narrated by Ahmad (7522, 9910) and Bazzar in Kashf Astar (1898), and Ibn Hibban graded it sahih (512), all of them through the route of Shubah, from Dawud bin Farahij, who said, I heard Abu Hurairah say, and he mentioned it. This chain is also hasan because of Dawud bin Farahij, for although there is disagreement about him, he is hasan al-hadith, and he is among the men listed in Tajil.