Sayyiduna Abdullah bin Amr (may Allah be pleased with him) reports that the Prophet (peace and blessings be upon him) said: "Whoever harms the people of Madinah, Allah Almighty will afflict him with harm. Upon him will be the curse of Allah Almighty, of the angels and of all mankind; Allah Almighty will accept no obligatory or voluntary worship of his."
Imam al-Tabarani recorded it in al-Mu'jam al-Kabir; its chain contains a narrator, al-Abbas bin al-Fadl al-Ansari, who is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الحج / 5826