The Messenger of Allah ﷺ said, "O Allah, bless the people of Madinah in their mudd." He continued the hadith, in which he said, "Whoever intends harm against its people, Allah will dissolve him as salt dissolves in water."
قال رسول الله ﷺ: اللهم بارك لأهل المدينة في مدهم وساق الحديث وفيه: من أراد أهلها بسوء أذابه الله كما يذوب الملح في الماء.
Muslim reported it in the Book of Hajj (1387:495) from Abu Bakr bin Abu Shayba, who said, Ubaydullah bin Musa told us, Usama bin Zayd told us, from Abu Abdullah Qarraz, who said, I heard him say, I heard Abu Hurairah and Saad both saying [the following], and he mentioned it. The lengthy hadith to which Muslim referred is the one that follows.