What will it mean for believers to be fully conformed to the image of Jesus in the world to come? No doubt, there are many answers that could be given to this question.
The first is that all of them will be sinless, without a trace of sin. That will be an amazing transformation, to be without sin inwardly and outwardly, to have pure affections and thoughts as well as actions. Never again will they confess sins, although in the new world where they will be perfectly conformed to the image of the Son they will never forget that once they were sinners in this world that is passing away.
Second, when they are perfectly conformed to the image of Jesus they will be shining with glory. We can think of the majestic description of Jesus glorified in heaven that is given in Revelation 1. We know that Jesus will always remain unique, far above his people. Yet he does say in Matthew 13:43 that his people will shine as the sun in the kingdom of the Father. That is an amazing description. Think of the effects of the shining of the sun in the sky. It changes everything for the better, makes life more pleasant and enjoyable. The people of God will stand out among the entire restored creation of God, not because of anything they are in themselves, but because of the great blessings that will be given to them graciously in the world to come.
Third, the people of God in that wonderful future experience will share the kingdom. Gone will be the petty jealousies and infantile remarks that are often found among them in this world. Instead they will be competent, through the work of God in them, to share the kingdom that has been prepared for them. As they share in the blessings of the eternal world they will discover the full meaning of fellowship. And as they share, they will discover that what they possess does not decrease because they are now in the place where nothing is lost.
Fourth, the people of God, when that great occasion comes, will be sons of God in the fullness of what that status will mean. Of course, there will remain an eternal difference between the divine Son and the forgiven sons. Yet although that distinction will always remain, it will also be the case that each of the sons will now find themselves in their inheritance, and discovering that, now they have been conformed to Jesus, the creation has ceased to groan and instead is now the suitable location in which Jesus and his people can dwell together forever.
We can see the distinction that will remain between Jesus and his people in the title that he is given in this verse. Jesus is the firstborn, which is a royal title rather than a title that suggests age.The reason why his people will have everything is because he has everything. He is the heir of all things, the ruler of the universe, and through their union with him his people share in the privileges and blessings of that status. But although they are sons of God, they will always remain the servants of Jesus. He will always be the firstborn.
Paul mentions another marvellous truth in this verse when he describes the number of people that will be conformed to the image of Jesus. He says that there will be many of them. Often we hear people comment about the size of families today and say that they are not as big as they used to be. Well here is a family that is unique as far as its number is concerned, and it is a great encouragement for us to know that they will be many members in the heavenly family. It will be a wonderful sight to see when it happens, but here in this chapter of Romans Paul invites to take a look at what is coming and rejoice in the certainty of it.