Abu Darda reported,
The Prophet ﷺ said, "Whoever defends the honor of his Muslim brother, it becomes binding upon Allah 
to shield him from the Fire of Hell on the Day of Resurrection."
Azami 14129
Hasanعن أبي الدرداء
عن النبي ﷺ قال: من رد عن عرض أخيه المسلم كان حقا على الله عز وجل أن يرد عنه نار جهنم يوم القيامة.
Ahmad (27536) and Ibn Abu Hatim, as mentioned by Ibn Kathir in his Tafsir, both narrated it through various chains, from Layth, from Shahr bin Hawshab, from Umm Darda, from Abu Darda, who related it. The wording given is Ahmad's, while in Ibn Abu Hatim's version he then recited this verse, "And it was incumbent upon Us to help the believers" [Rum 30:47]. Layth is Ibn Abu Salim, who has weak memory, but he is corroborated by another narrator.Tirmidhi (1931) narrated it from Ahmad bin Muhammad, who said, Ibn Mubarak informed us, from Abu Bakr Nahshali, from Marzuq Abu Bakr Taymi, from Umm Darda, from Abu Darda, who related it. Marzuq Abu Bakr Taymi is unknown. With this corroboration, the hadith rises to the level of hasan, and Tirmidhi indeed graded it hasan, saying, "This hadith is hasan."