From Sahih Muslim (Hadith 3319):
Amir b. Sa'd b. Abu Waqqas reported on the authority of his father (Allah be pleased with him) that Allah's Messenger (ﷺ) said, and then the (above-mentioned) hadith was narrated with this addition:" None should nurse ill-will towards the people of Medina, or Allah will melt him in fire like the melting of lead or the dissolution of salt in water
Reference: Muslim 3319