´'Abdullah bin Mas'ud narrated that the Messenger of Allah said:` "Verbally abusing the Muslim is disobedience and fighting him is disbelief." Zubaid said:"I said to Abu Wa'il: 'Did you hear it from 'Abdullah?' He said: 'Yes.'"
Hadith ReferenceSunan at-Tirmidhi / Chapters on Righteousness And Maintaining Good Relations With Relatives / Hadith: 1983