Simply deny it
Indeed it is said this means only: he sins not willfully; or he does not commit sin habitually; or, not as other men do; or, not as he did before. But by whom is this said? By St. John? No. There is no such word in the text, nor in the whole chapter, nor in all this letter, nor in any part of his writings whatever. Why then, the best way to answer a bold assertion is simply to deny it. And if any man can prove it from the word of God, let him bring forth his strong reasons (Isaiah 41:21).
1771 text
6. Indeed it is said, this means only, he sinneth not wilfully; or he doth not commit sin habitually; or, not as other men do; or, not as he did before. But by whom is this said? By St. John? No. There is no such word in the text: nor in the whole chapter; nor in all this epistle; nor in any part of his writings whatsoever. Why then, the best way to answer a bold assertion is, simply to deny it. And if any man can prove it from the word of God, let him bring forth his strong reasons.