1 John 5.11-13
John wrote his letter to the church against the dark background of error. There were those who were insisting that Jesus did not have a divine origin – that is, he had not “come in the flesh from God” (4:2). But John rightly insists that God had given them eternal life and that “this life is in his Son.” He leaves no doubt that if you have the Son you have life and if you don’t have the Son you don’t have life. John stresses the importance of having the Son because those who don’t have him, simply do not have eternal life (v. 12). The reason he clarifies this point is that some of the believers were beginning to wonder whether or not their salvation was secure – whether or not they had eternal life.
Doubts of that sort still tend to trouble many contemporary believers. Those who believe that they could lose their salvation live with considerable uncertainty. But, if eternal life is in the Son, and they “are in” the Son, then the future is secure. Since by definition the Son of God has life that never ends, it follows that if you are in the Son you will share in that life – you will live forever. John is crystal clear on the issue and hopefully all believers will come to enjoy the same confidence.
Once again we are reminded that Satan, although defeated at Calvary, is still very much around. Undermining believers’ security is a primary method of achieving his goal. Doubt is the weapon he uses just as he did in the Garden when Eve was tempted with Satan’s, “Did God really say?” Even 2,000 years later he watches for an opening when he can suggest the possibility, “Does God really mean that?” Confidence is essential in the Christian’s life because apart from it, life looses its bright future. Among other things, lack of certainty undermines effective prayer (v. 14). To be theologically confident leads to a more fruitful life. And isn’t bearing fruit what we are to be doing? I known that the Christian faith would have ever grown from that handful of Galilean peasants to become the dominant factor in the westward expansion of Christianity if our religious forefathers had been doubtful about the person of Christ?
Yes, eternal life is in the Son and we are in the Son. So it follows that we have eternal life. As John puts it, “I write these things . . . so that you may know that you have eternal life” (v. 13).