Being a son of God is not simply a nice term for Christians to claim because we call God “our Heavenly Father”. The privilege of becoming a son of God doesn’t just come by a confession of a sinner’s prayer, attending church regularly, or even by avidly studying the Word of God. Yes, these are all important steps along the way, but there is a much greater understanding of becoming a son of God. John the Revelator writes in Revelations 21:7 that the sons of God receive the inheritance, and Revelations 20:4-6 tells us what that inheritance is. Ultimately, it is the sons of God who rule and reign in the millennial kingdom, so it is imperative we understand who a true son is. Through exploration of Scripture and the Early Church writings, we can gain a greater understanding of some of the important characteristics and telling signs of a true son of God. Then, prayerfully, we will be able to discern if we are on the path to becoming a son of God or the areas we need to adjust our focus.
Sons are led by the Holy Spirit
Apostle Paul clearly writes that the sons of God are those led by the spirit of God (Romans 8:14). Being “led” is not a passive word, it is an action word. To be led in something means to be engaged and actively following. The word spirit in Hebrew is ‘ruach’ and in the ancient Hebrew language, it is strongly connected to the word for road, path, caravan, and millstone . These words all have a common thread: they are all to do with following the same path to get to a destination. In this case, the destination is the inheritance of the Kingdom as previously mentioned. So, Scripture is telling us that the Spirit is our guide to lead us into all truth (John 16:13). But we don’t stop there. John doesn’t just mean that the spirit is there to guide us to “Jesus”, but into all truth. The Greek word for ‘truth’ means: Truth as opposed to types, emblems, shadows . Another word for types and shadows is parables, which is important to note because when the disciples ask Jesus why he speaks to the crowds in parables he replied to them, “To you it has been granted to know the mysteries of the kingdom of heaven, but to them it has not been granted,” (Matthew 13:11 AMP). Jesus further explained the reason He speaks to the crowds in parables is “because while [having the power of] seeing they do not see, and while [having the power of] hearing they do not hear, nor do they understand and grasp [spiritual things],” (Matthew 13:13 AMP). It is not enough for us to stop at just reading the parables of scripture, but Jesus requires us, just like His disciples, to understand the mystery of the kingdom hidden inside the parable. In 1 Corinthians 2:10-11, Paul gives us more insight into the function of the spirit: “The spirit searches all things, yes the deep things of God”. The word for deep in Greek is ‘bathos’, which means the secret, unrevealed purposes of God  and (figuratively) mystery . Paul is telling us here that the spirit is what reveals the mystery of God to those with spiritual eyes to see and ears to hear.
Clement of Alexandria, confirms that the sons of God are those who receive the mysteries of God:
Blessed be our Lord, brethren, who has put into our hearts wisdom, and the understanding of His secrets. For the prophet says, “Who shall understand the Lord’s parable but the wise and understanding, and he that loves his Lord?” It is but for few to comprehend these things. For it is not in the way of envy that the Lord announced in a Gospel, “My mystery is to me, and to the sons of my house;” .
Clement states above that the understanding of the mysteries of God is given to the sons of God, and as Paul wrote, the revealing of the mysteries comes by the Holy Spirit. Clement explains that understanding the mysteries and secrets of God is receiving God’s wisdom. What a powerful statement and something we should all want as believers! However, just as we started off in Romans 8:14, being led by the spirit is an active participation, not just reading or hearing, but actively walking in the understanding we are receiving from the spirit to gain the wisdom hidden within the parables.
Sons are chastised
Apostle Paul explains to the body of Christ, that God chastises those whom He loves, and he encourages us to persevere through the chastening so that God sees us as sons:
“And you have forgotten the exhortation which speaks to you as to sons: “MY SON, DO NOT DESPISE THE CHASTENING OF THE LORD, NOR BE DISCOURAGED WHEN YOU ARE REBUKED BY HIM;FOR WHOM THE LORD LOVES HE CHASTENS, AND SCOURGES EVERY SON WHOM HE RECEIVES.” If you endure chastening, God deals with you as with sons; for what son is there whom a father does not chasten? But if you are without chastening, of which all have become partakers, then you are illegitimate and not sons.” (Hebrews 12:5-8).
Apostle Paul likens the chastening of God to that of a good father to a son, in the natural sense. Those who were fortunate enough to have a father (or parents) that corrected and disciplined them in love, may not have liked it at the time, but realised the benefit as they grew older, and now are grateful for it. On the other hand, those who experience discipline from a parent or guardian that comes out of a place of anger, usually brings about a feeling of anxiety and fear in the child; ultimately causing them to shy away from discipline and see it as a punishment, rather than a form of correction and love to bring them back into the right way. Studies show that lack of (fair) discipline and correction in a home whilst a child is growing and developing can be a key cause for violence, crime, and unruly behavior later in life . Jesus, speaking to John regarding the lukewarm church says: “As many as I love, I rebuke and chasten. Therefore, be zealous and repent,” (Revelation 3:19).
Chastening from God is always fair because God is just (Psalms 25:8) and He does not act out of emotion. In fact, part of the definition for chastening is “whatever in adults also cultivates the soul, especially by correcting mistakes and curbing passions”, and “instruction which aims at increasing virtue” . Another meaning for virtue is the nature/character of God. So, through the chastening of God, He wants us to turn from our carnal nature and come into His character.
St. Clement of Rome writes the following:
We must accept correction, dear friends. No one should resent it. Warnings we give each other are good and thoroughly beneficial. For they bind us to God’s will. This is what the holy Word says about it: “The Lord has disciplined me severely and has not given me up to death. For the Lord disciplines the one he loves, and punishes every son he accepts.” … Do not refuse the Almighty’s warning. For he inflicts pain and then makes us all well again. He smites, but his hands heal. 
Notice the last part of Clement’s writing saying God inflicts pain and then heals. When we choose not to obey the Word of God, God brings the discipline to teach us not to go astray. If we heed the discipline and turn back to Him, that is when he brings the healing. Just like in the natural when a good parent disciplines their child for something they were told not to do. Once the discipline is delivered and the child sees what they did wasn’t right, the parent receives the child back. However, God does more than just receive us back, he brings healing to the wounds in our heart once we return to Him. God always wants us to repent and turn back to Him, but if we reject the chastening of the Lord or shy away from it, how can we expect to come into true sonship? God can also heal us from a fear of chastening. He wants to heal the wounds in our hearts that prevent us from receiving His correction that brings us to repentance.
Sons are the overcomers, who reign with God
Back to where we started in Revelation 21:7, “He who overcomes shall inherit all things, and I will be his God and he shall be My son.” What is the inheritance of all things? Jesus tells John in Revelation 2:17, “To him who overcomes I will give some of the hidden manna to eat. And I will give him a white stone, and on the stone a new name written which no one knows except him who receives it.” The overcomers receive the glory of God (the ark of the covenant is in the Holy of Holies, which contains the Glory of God), and the overcomers are those who reign with God for the millennial Kingdom (Revelation 2:11, 20:6). Revelation 3:5 says that the overcomers will not be blotted out of the Book of Life. From this scripture we can understand that those who do not overcome will be blotted out of the Book of Life. What exactly is it that we are overcoming? Revelation 21:8 tells us the traits of the ones that do not overcome- the defeated ones, which are the vices and passions of the flesh. It is our carnal nature, that is at war with the mind of Christ, that the sons of God overcome and take dominion over the power those vices once had over us, bringing freedom from bondage and inner healing (Romans 8:6-8).
Cyprian, a third-century Early Church father writes:
“If we are the sons of God, if we are already beginning to be His temples, if, having received the Holy Spirit, we are living holily and spiritually, if we have raised our eyes from earth to heaven, if we have lifted our hearts, filled with God and Christ, to things above and divine, let us do nothing but what is worthy of God and Christ, even as the apostle arouses and exhorts us, saying: “If ye be risen with Christ, seek those things which are above, where Christ is sitting at the right hand of God; occupy your minds with things that are above, not with things which are upon the earth. For ye are dead, and your life is hid with Christ in God. But when Christ, who is your life, shall appear, then shall ye also appear with Him in glory.” (Col 3:1-4) Let us, then, who in baptism have both died and been buried in respect of the carnal sins of the old man, who have risen again with Christ in the heavenly regeneration, both think upon and do the things which are Christ’s . . .” 
Cyprian teaches us that by living a lifestyle pleasing to God, by fixing our minds on heavenly things, we can overcome our carnal nature thus being regenerated in Christ’s nature through the baptism of the Word of God. Raising eyes from earth to heaven is referring to having deeper understanding and seeing the Word spiritually, not just carnally, like we explored previously- having the understanding of the mysteries of God.
The sons of God are a privileged minority according to Scripture who are walking in the spirit, understanding the deeper mysteries of the scripture, and applying it to their walk. They welcome the just discipline of God, knowing that it brings them back into alignment with the perfect will of God for their own benefit of salvation. Sons manifest Christ’s nature by overcoming the carnal beastly nature (of man) and ultimately, the sons of God are those who receive salvation. They rule and reign with Christ. I only touched the surface of Scripture in this article and there is much more to be explored on the matter, but I pray this has allowed you a much deeper understanding of what a true son is, and how we can examine our hearts to see if we are on the way to becoming one of God’s sons.
1. Ancient Hebrew Lexicon Bible Dictionary: Spirit (H7307)
2. Word Study Dictionary: Truth (G225)
3. Complete Word Study Dictionary: Deep (G899)
4. Strong’s Bible Dictionary: Deep (G899)
5. Clement- Stromata, Bk 5, Ch X (Ante Nicene Fathers Volume 2)
6. Sathyanarayana Rao, TS. “Criminal behavior: A dispassionate look at parental disciplinary practices”. 2007 Oct – Dec https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2910344/
7. Thayer’s Greek Lexicon Dictionary: Chasten (3809)
8. Clement- First Epistle
9. Cyprian- Treatise of Cyprian, Vol X (Ante Nicene Fathers Volume 5)
All scripture taken from the NKJV unless otherwise stated.