The Prophet ﷺ said, "Whoever defends a believer from a hypocrite, Allah will send an angel to protect his flesh on the Day of Resurrection from the fire of Hell. And whoever accuses a Muslim of something, intending to disgrace him by it, Allah will detain him on the bridge of Hell until he retracts what he said."
حدثنا عبد الله بن محمد بن أسماء بن عبيد حدثنا ابن المبارك عن يحيى بن أيوب عن عبد الله بن سليمان عن إسمعيل بن يحيى المعافري
عن النبي ﷺ قال من حمى مؤمنا من منافق أراه قال بعث الله ملكا يحمي لحمه يوم القيامة من نار جهنم ومن رمى مسلما بشيء يريد شينه به حبسه الله على جسر جهنم حتى يخرج مما قال
[Its chain of transmission is daif] Ahmad narrated it, 3/441, from the hadith of Abdullah bin Mubarak, transmitted through him. It is also found in his Zuhd, no. 686. Ismail bin Yahya is unknown, no one has affirmed his reliability except Ibn Hibban.