There are many things concerning the future that we have not received information about in the Bible. Yet we are told some things and John does give one important detail about what will happen to God’s children when Jesus returns – they will become like him when they see him.
What does John mean by this prospect of likeness? He does not mean that believers will possess divine attributes such as omniscience, omnipotence and omnipresence. The likeness is connected to the humanity of Jesus. Yet being like him will not mean that they will become as great as him – he will always be far superior.
Christ’s humanity will be the model for redeemed humanity. This is the destiny of each child of God – full conformity to the image of Jesus. We shall be like him physically (perfect body with no weaknesses), we shall be like him in the sense that we will be under the enabling influences of the Holy Spirit, and we shall be like him in having a capacity for absorbing and delighting in the glory of God.
No doubt, the child of a rich person could say, ‘I have this wonderful status. One day I will inherit all that my father has promised. I cannot tell you at this stage what it has or what it is worth, but I know that it is worth waiting for.’ A Christian will think the same. He will be amazed at his status as a son of God and astounded by the prospects ahead.
John then reminds his readers of the inevitable outworking of a proper attitude to the future appearance of Jesus. Those who look forward to it will purify themselves from sin and its defilement. They desire sanctification in the present because it enables them to become increasingly like Jesus now as they anticipate perfect likeness when he returns. The best way for them to prepare for life with Jesus in heaven is by holy living while on earth.