a world of wickedness: The tongue (our speech) acts as an agent of the whole unrighteous world that opposes God (1:27; 4:4).
by hell: The Greek word Gehenna refers to the place of eternal punishment (Matthew 5:22, 30; 23:15). Hades is the place of the dead (Luke 16:23; Acts 2:31). Mentioning hell points to the devil as the ultimate source of evil speech (James 4:7; Matt 5:22; John 8:44).