Are yams and sweet potatoes the same?
c.1300, from Anglo-French vengeaunce, Old French vengeance "revenge," from vengier "take revenge," from Latin vindicare "to set free, claim, avenge" (see vindicate).
Vengeance is mine, ... saith the Lord. Therefore if thine enemy hunger, feed him; if he thirst, give him drink; for in so doing thou shalt heap coals of fire upon his head. [Paul to the Romans, xii:19-20]