1 John 2:26-27
26 I write these things to you about those who are trying to deceive you. 27 But the anointing that you received from him abides in you, and you have no need that anyone should teach you. But as his anointing teaches you about everything, and is true, and is no lie--just as it has taught you, abide in him.
Why did John write his first epistle? Well, all of his epistles were written after he had received the “Revelation of Jesus Christ.” His overall purpose in writing these epistles was to help the saints understand the unveiling of the events revealed in Revelation. The times in which this would apply would be tumultuous; they would be chaotic. Believers at this time would be under tremendous pressure both from without and within the “church”. It would be a time when there would be a very real danger of believers being misled, of their being deceived. So John’s purpose is understandable; he wants to prevent believers from being deceived. So He writes the first epistle to provide milestones, standards, criteria and a method of focus for the disciples of Jesus to get through these times. As you read the epistle, one can see the commonsense guidelines that the beloved apostle provides for us, the end-time saints.