31 So Jesus was saying to those Jews who had believed Him, “If you continue in My word, then you are truly disciples of Mine; 32 and you will know the truth, and the truth will make you free.” 33 They answered Him, “We are Abraham’s descendants and have never yet been enslaved to anyone; how is it that You say, ‘You will become free’?”

34 Jesus answered them, “Truly, truly, I say to you, everyone who commits sin is the slave of sin. 35 The slave does not remain in the house forever; the son does remain forever. 36 So if the Son makes you free, you will be free indeed. 37 I know that you are Abraham’s descendants; yet you seek to kill Me, because My word has no place in you. 38 I speak the things which I have seen with My Father; therefore you also do the things which you heard from your father.”

39 They answered and said to Him, “Abraham is our father.” Jesus *said to them, “If you are Abraham’s children, do the deeds of Abraham. 40 But as it is, you are seeking to kill Me, a man who has told you the truth, which I heard from God; this Abraham did not do. 41 You are doing the deeds of your father.” They said to Him, “We were not born of fornication; we have one Father: God.” 42 Jesus said to them, “If God were your Father, you would love Me, for I proceeded forth and have come from God, for I have not even come on My own initiative, but He sent Me. 43 Why do you not understand what I am saying? It is because you cannot hear My word. 44 You are of your father the devil, and you want to do the desires of your father. He was a murderer from the beginning, and does not stand in the truth because there is no truth in him. Whenever he speaks a lie, he speaks from his own nature, for he is a liar and the father of lies. 45 But because I speak the truth, you do not believe Me. 46 Which one of you convicts Me of sin? If I speak truth, why do you not believe Me? 47 He who is of God hears the words of God; for this reason you do not hear them, because you are not of God.”

via John 8 NASB – The Adulterous Woman – But Jesus went – Bible Gateway.

So that settles it. Only believers are God’s children. Not every person is God’s child.

Except… Paul told the Athenian unbelievers that they themselves knew that they were all God’s children.

²² So Paul stood in the midst of the Areopagus and said, “Men of Athens, I observe that you are very religious in all respects. ²³ For while I was passing through and examining the objects of your worship, I also found an altar with this inscription, ‘TO AN UNKNOWN GOD.’ Therefore what you worship in ignorance, this I proclaim to you. ²⁴ The God who made the world and all things in it, since He is Lord of heaven and earth, does not dwell in temples made with hands; ²⁵ nor is He served by human hands, as though He needed anything, since He Himself gives to all people life and breath and all things; ²⁶ and He made from one man every nation of mankind to live on all the face of the earth, having determined their appointed times and the boundaries of their habitation, ²⁷ that they would seek God, if perhaps they might grope for Him and find Him, though He is not far from each one of us; ²⁸ for in Him we live and move and exist, as even some of your own poets have said, ‘For we also are His children.’ ²⁹ Being then the children of God, we ought not to think that the Divine Nature is like gold or silver or stone, an image formed by the art and thought of man. ³⁰ Therefore having overlooked the times of ignorance, God is now declaring to men that all people everywhere should repent, ³¹ because He has fixed a day in which He will judge the world in righteousness through a Man whom He has appointed, having furnished proof to all men by raising Him from the dead.”

Paul is referring to creation here. It it worth pointing out that, in Genesis 5.1-3, being a son and bearing an image of the father are related to one another:

¹ This is the book of the generations of Adam. In the day when God created man, He made him in the likeness of God. ²He created them male and female, and He blessed them and named them Man in the day when they were created.  ³ When Adam had lived one hundred and thirty years, he became the father of a son in his own likeness, according to his image, and named him Seth.

Luke 3.38 explicitly tells us that Adam was God’s son, but we could infer it from Genesis 5.1-3 even it if he didn’t spell it out for us. In systematic theology, Christians have affirmed that even unbelievers are still made in God’s image, though the image is distorted. Wouldn’t this also require an affirmation that unbelievers are still God’s children in some sense?

Then there is the parable of the prodigal son. Notice how it is the son who believes he can no longer be anything but a servant to the man who was his father, and the father does seem to affirm that, for a time, the child’s status of sonship was gone:

¹⁷ But when he came to his senses, he said, ‘How many of my father’s hired men have more than enough bread, but I am dying here with hunger! ¹⁸ I will get up and go to my father, and will say to him, “Father, I have sinned against heaven, and in your sight; ¹⁹ I am no longer worthy to be called your son; make me as one of your hired men.”’ ²⁰ So he got up and came to his father. But while he was still a long way off, his father saw him and felt compassion for him, and ran and embraced him and kissed him. ²¹ And the son said to him, ‘Father, I have sinned against heaven and in your sight; I am no longer worthy to be called your son.’ ²² But the father said to his slaves, ‘Quickly bring out the best robe and put it on him, and put a ring on his hand and sandals on his feet; ²³ and bring the fattened calf, kill it, and let us eat and celebrate; ²⁴ for this son of mine was dead and has come to life again; he was lost and has been found.’ And they began to celebrate.

One other piece of data, from Matthew 21:

²⁸ “But what do you think? A man had two sons, and he came to the first and said, ‘Son, go work today in the vineyard.’ ²⁹ And he answered, ‘I will not’; but afterward he regretted it and went. ³⁰ The man came to the second and said the same thing; and he answered, ‘I will, sir’; but he did not go. ³¹ Which of the two did the will of his father?” They *said, “The first.” Jesus *said to them, “Truly I say to you that the tax collectors and prostitutes will get into the kingdom of God before you. ³² For John came to you in the way of righteousness and you did not believe him; but the tax collectors and prostitutes did believe him; and you, seeing this, did not even feel remorse afterward so as to believe him.

Now here is my question: if one of the sons was not really of son of the father, wouldn’t his disobedience be less serious and less sinful? Here, denying sonship would not mean condemnaton but, to a degree, exoneration.

Of course, there are also other passages that link up with John 8 (Ephesians 2 might apply in a similar way, for example). Some refer to Israel as distinctively God’s son, which would probably have something to do with the way Jesus spoke to his fellow countrymen in his parable of the two sons in Matthew 21.

So which is it?

I don’t see why we have to decide. Why would the Bible have to use the same language at all times and places to communicate. It seems to me that language and imagery communicate just fine without having a universal code in place for every image or metaphor.

This is how I see it:

1. If you proclaim that God is the father of all people and that all people are His children in order to give unbelievers false hope that prevents them from repenting and calling on Jesus, or that discouraged Christians from evangelizing, then you are lying.
2. If you proclaim that God is the father of all people and that all people are His children to give unbelievers hope that they will be received if they repent and believe, and to impress Christians with their obligation to evangelize, then you are telling the truth.
3. If you proclaim that God is only the father of believers in order to discourage unbelievers from repenting and calling on Jesus, then you are lying.
4. If you proclaim that God is only the father of believers to encourage unbelievers to come back and be adopted, and to encourage believers that God has save them, then you are telling the truth.