John Calvin's Commentary on the Bible

4 (1 John 2:4)

Verse 4

4He that saith, I know him How does he prove that they are liars who boast that they have faith without piety? even by the contrary effect; for he has already said, that the knowledge of God is efficacious. For God is not known by a naked imagination, since he reveals himself inwardly to our hearts by the Spirit. Besides, as many hypocrites vainly boast that they have faith, the Apostle charges all such with falsehood; for what he says would be superfluous, were there no false and vain profession of Christianity made by man.

- John Calvin's Commentary on the Bible