Previously I began to look at John 3:16 for a friend of mine. As part of that discussion I looked at the title "Son of God" and how that title is used and what it means. However, part of the question my friend asked had to do with how the Son of God is different from sons of God. That is, what makes Christ so terribly important compared with anyone else who might be called a son of the living God? To answer this question we have to first understand who Christ is, only then do we understand the importance of what it means that we are called sons of God.
Now, in part, I've already written my thoughts on what it means that Christ is the Son of God. There is much to be said on this issue, and while I'm not familiar with any, I'm sure there are books devoted to the issue of Christ being the Son of God. There is no way I could, in one post, one day, one week, or even in one life time, truly explore every facet of Christ as the Son of God. So please be aware that this will be an imperfect post. There are some things I might write here that are not as theologically accurate as they could be, or should be, and there are going to be many things I will not say that are still very important. I want to encourage you, my dear reader, to be thoughtful on this subject, explore it as there is a vast richness in thinking on Christ and seeking to know both the Son and the Father.
First of all, the fact that Christ is the Son of the God points to his own divinity. Christ is God incarnate. This is a unique statement about Christ that cannot be made about any other man, ever. The fact of the trinity is seen in the fact that the Son who comes from the Father, is just like the Father. As men have sons who are like them, so the Son of God is like the Father, he is God. We looked at this somewhat previously when we considered the title "Son of God" and noted the way the early church chose to express this: "True God from True God."
Christ is also the beloved of the Father. John Piper once said that God is not an idolater. I don't care how much you may agree or disagree with Dr. Piper, here I think we must all agree. God is not an idolater, therefore he does not worship anything other than God, and he does not love anything more than he loves God. Thus, again, the trinity becomes crucially important for us to understand Christ as "Son of God."
You see, as Christ is God, he is also the Son and not the Father. Therefore the Father, in his holiness, loves the Son completely, for he loves God. And the Son worships the Father and gives him glory (as we see in Luke 4:8 in his response to Satan). The Spirit, who acts to bring us to Christ and who remains with us as the counselor and comforter that was promised, thus points us to the triune person of God, so that we should worship Father, Son, and Holy Spirit, the eternal God. Without understanding (as far as we may) the trinity we would not rightly understand the reality of the relationship of the Father and the Son. This understanding of how the Son worships the Father, and the Father loves the Son, is not all that may be said, but it is a sufficient place for us to begin understanding who we are in Christ.
What we have so far is that Christ is God, and that Christ is loved by God and in perfect relationship with God. As the only begotten Son of God these are unique characteristics of Christ, but they are also, in part, passed on to those of us who are sons of God. Theologians have long differentiated between what may be called the communicable and incommunicable attributes of God. There are also, as a way of speaking, communicable attributes of the Son of God that are passed down to those who are called "sons of God" by the Father. These are attributes that we gain from God.
While we may not have divinity, part of what it means to be one of the sons of God is participate in God's holiness. The Eastern Orthodox Church has long understood this and has embraced the teaching in a way that is absent from much of the Western Church, and I would say this is particularly true of the Protestant church. Consider that Peter says in 2 Peter 1:4, we have become partakers in the divine nature. Now, the Eastern Orthodox Church, essentially, argues that we become as holy as God himself, but I think that may be stretching matters a bit. Yet, Christ himself said that we are to be holy as our Father in Heaven is holy. So, we are to participate in God's holiness, through the Son. In becoming sons of God we are made into holy creatures, separate from the world around us (in the world but not of the world).
Not only do we have holiness because of our relationship with Christ, but we also have relationship with the father. This is the most obvious of the meanings of "sons of God." This title is not shared by all humanity, that is not all men are sons of God. All men are made by God, but only those who are adopted through the Son may be rightly called sons of God. Therefore, only those who have been adopted by the Son, through the work of the Spirit into the family of God have the right of claiming special relationship to the Father, all others, while they can claim to be offspring, made by God, are alienated from the Father by sin, and therefore may not, and indeed will not, draw near to God.
As part of our unique relationship with God we have access to the love of God in a special way. God calls us to prayer, desiring to hear and answer our requests. He draws us to himself through the Spirit, desiring our presence with him and enjoying our praise (for he is worthy). The Father cares for us, inviting us to eat with the Son at the great wedding feast prepared for the guests of the groom. And the Father sees us as the image of Christ, disciplining us and building us up that we might one day participate in his glory.
To be one of the sons of God is an amazing thing. It is nothing to be haughty about though, as Paul points us that we have nothing that we were not given. Our salvation which began our sanctification and guaranteed our eventual resurrection was not something we earned or somehow purchased, but rather it was given us a gift of God. We were sinners, vile, unholy, and detestable; the very enemies of God and at war with him. Yet God, in his kindness, chose us in the Son, calling us to himself and giving us faith that we might believe and be saved. "For by grace you have been saved through faith. And this is not your own doing; it is the gift of God, not the result of works, so that no one may boast."
We are the sons of God who have been redeemed by the blood of the Son. Let us so walk and so act. Let us not glory in ourselves but glory in him who saved us. We are in a special position; but our position is nothing to be haughty about, for we must take care to be sure we stand, lest we fall. It is not for our glory that God adopted us or has promised to one day share his glory with us, but it is because this will result, somehow, in even greater glory to the Father that he has so ordained. Humility constrains us not to brag but to graciously share the truth of God and, with reverence, to enjoy the relationship that God has given us who are his children.