The Messenger of Allah ﷺ said, "Whoever believes in Allah and the Last Day, let him not harm his neighbor. Whoever believes in Allah and the Last Day, let him honor his guest. Whoever believes in Allah and the Last Day, let him speak good or remain silent."
حدثنا عبد الرزاق حدثنا معمر عن الزهري عن أبي سلمة
قال رسول الله ﷺ من كان يؤمن بالله واليوم الآخر فلا يؤذي جاره من كان يؤمن بالله واليوم الآخر فليكرم ضيفه من كان يؤمن بالله واليوم الآخر فليقل خيرا أو ليصمت
Its isnad is sahih. Bukhari related it in 11:425 through Ibrahim bin Saeed, and Muslim in 1:29 through Yunus, both of them from Zuhri, with this same isnad, in similar wording. Bukhari also related it in 10:373 and 442, and Muslim in 1:29, through other routes, from Abu Salih, from Abu Hurairah, with similar wording. Its meaning has already appeared at 6261, from the hadith of Abdullah bin Amr bin As.As for his statement, "let him not harm," it is recorded here in this form with the letter ya retained, despite it being a jussive expression of prohibition. This is grammatically sound and correct in Arabic, with many supporting examples.