It is sad, but many who talk about our Saviour and use His name do not believe that He is the eternal God, the Creator of all things, and that He came to die for the sins of mankind.
In the verses previous to this, the apostle discussed false teachers who talk about Jesus but fail to acknowledge that He truly is the Son of God. Such people are representatives of Satan, not messengers of God. They speak the type of message that the world loves to hear. Often based on human philosophy, it caters to the pride of intellect so prized by most people. Such teachers and those who delight in their teaching are unbelievers. Where, then, do you stand with reference to this matter? If you agree with them, then you, too, need to be born again.
On the other hand, how do I know that I am of God? I believe His Word. I believe that Jesus Christ is the eternal God, that He dwells in a glorified human body and that I shall be like Him, for one day I shall see Him as He is. I have no doubt about it. The people who are of God will accept this message, but those who are of the world will reject it. Classify yourself according to your attitude. It will let you know whether or not you are saved.
"Ye are of God, little children, and have overcome them: because greater is he that is in you, than he that is in the world" (1 John 4:4).