This thesis investigates the English translations of the Greek phrase τῷ πονηρῷ in 1 John 5:19, which have interpreted it as “the evil one” (Personal Evil) or“wickedness” (Abstract Evil). By examining Greek and Latin texts, early church interpretations, modern commentaries and translation history, the study argues that the original context supports a Personal Evil interpretation (Satan). It reveals that the Abstract Evil (wickedness) renderings did not stem from the Latin Vulgate.