2:2 letter. This reference does not prove there was a forged letter bearing Paul’s name already in existence, but only that Paul saw this as a possibility. Word may have reached him that the new teaching was circulating with some pretense of having his authority. Paul’s injunction is meant to ensure that no vehicle of instruction—even one supposed to have come from him—should be heeded if it asserts that the day of the Lord has already come (cf. Gal. 1:8).