ISB ~ 1 John 3 v12

like Cain:The only direct reference to the OT in 1 John.

• The actions of Cain constitute the first example of fraternal hatred in the Bible (Gen 4:1-16). His envy of Abel mirrored the devil’s envy of Adam (Wis 2:24); so the murderous act that ensued made him a child of the devil, who was a “murderer from the beginning” (Jn 8:44). John is saying that hatred among fellow Christians is on a par with homicide (1 Jn 3:15).