Terry Griffith argues in his Keep Yourselves from Idols that the odd closing exhortation of 1 John  (“little children, guard yourselves from idols”) holds the key to the book as a whole.   He also argues that the “Jewish matrix of Johannine tradition has been significantly underplayed.”  For the last couple of centuries, 1 John has been read as a response to doceticizing or gnosticizing movements within the early, with the specifics of the debate being filled out by reference to 2d-century evidence.  Griffith’s book attempts to show that “1 John is the product of a continuing debate between Jews and Jewish-Christians over whether Jesus was the Messiah, at a time when some Jewish-Christian belonging to Johannine Christianity had reverted to Judaism.”