3 John 1:4 - Dummelow's Commentary on the Bible

Greater] In the Gk., a double comparative, as in English 'betterer' would be. This may indicate that the author was not a classical Greek scholar, or the usage may be intentional, for emphasis, like the comparative formed on a superlative in Ephesians 3:8. Cp. also, 'How much more elder art thou than thy looks!' ('Merchant of Venice,' IV, i).