The slave does not remain in the family forever, but the son remains forever. (Jn. 8:35 NET)
3 Answers
The verse in the question is taken from a fairly long conversation, which covers most of the chapter, of Jesus and the Jewish leaders.
John 8:32 And ye shall know the truth, and the truth shall make you free.
8:33 They answered him, We be Abraham's seed, and were never in bondage to any man: how can you say, Ye shall be made free?
8:34 Jesus answered them, Verily, verily, I say unto you, Whosoever is committing sin is the servant (or slave) of sin.
8:35 And the servant (or slave) abides not in the house for ever: [but] the Son abides ever.
8:36 If the Son therefore shall make you free, ye shall be free indeed.
A slave is not part of the family, he just works there for awhile. He can be sold, or hired out. The son, on the other hand, is part of the family, he is heir of the family estate, and stays to inherit his father's property since it is his home.
It's fairly obvious in the dialogue with the Jewish leaders, that Jesus does not count them as "sons" of God. Jesus outright tells them, they are plotting to kill Him, (a grave sin) and their father is the devil.
The Jews in turn claim Abraham as their Father, thus suggesting they are of the chosen race, therefore children of God.
Who is the "slave" -- the unbelieving Jews clinging to their sin, and rejecting their Savior who could make them free.
Vs 8:36 If the Son therefore shall make you free, ye shall be free indeed.
They are seeking to kill him, not follow Him. They are convinced in their own minds that Jesus is a threat to them.
Jesus isn't talking about genetic relationships here. "I know that you are seed of Abraham" he tells them, but that relationship won't free them from the bondage of sin nor the condemnation of sin. Jesus is speaking of spiritual relationship, something that is on an altogether higher plain.
So who are the "sons"?
John 8:31 Then said Jesus to those Jews which believed on him, If ye continue in my word, then you are my disciples indeed;
8:32 And you shall know the truth, and the truth shall make you free.
John 1:12 But as many as received him, to them gave he power to become the sons of God, [even] to them that believe on his name:
1:13 Which were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God.
Galatians 4:5 [God sent forth His Son] To redeem them that were under the law, that we might receive the adoption of sons.
4:6 And because ye are sons, God has sent forth the Spirit of his Son into your hearts, crying, Abba, Father.
4:7 Wherefore you are no more a servant, but a son; and if a son, then an heir of God through Christ.
1Now I say, That the heir, as long as he is a child, differeth nothing from a servant, though he be lord of all; 2But is under tutors and governors until the time appointed of the father. 3Even so we, when we were children, were in bondage under the elements of the world: 4But when the fulness of the time was come, God sent forth his Son, made of a woman, made under the law, 5To redeem them that were under the law, that we might receive the adoption of sons. 6And because ye are sons, God hath sent forth the Spirit of his Son into your hearts, crying, Abba, Father. 7Wherefore thou art no more a servant, but a son; and if a son, then an heir of God through Christ. [Galatians 4:1-7 KJV]
In this passage Paul sets forth the experience of being born again in the context of experience of being freed from bondage to the law.
Receiving the Holy Spirit (after repentance towards God and after faith in the Lord Jesus Christ) the redeemed are brought into the experience of sonship by the indwelling Spirit whereby they cry Abba, Father, (see Mark 14:36 and Romans 8:15 and Galatians 4:6).
This directly relates to what Jesus expresses in John 8:35.
Genesis 16:1-2
"Now Sarai, Abram's wife, had borne him no children. And she had an Egyptian maidservant whose name was Hagar." NKJV.
A maidservant was a servant. When Sarai suggested to Abram "Please, go into my maid" this came as man's solution, or works, not faith in God's promises to provide, as in Genesis 15:4.
Genesis 21:10
"Therefore she [Sarah] said to Abraham, "Cast out this bondwoman and her son; for the son [Ishmael] of this bondwoman shall not be heir with my son, namely with Isaac". [My brackets].
The servant was cast out.
Genesis 22:20
"And He [the Angel of the LORD] said, "Do not lay your hand on the lad, or do anything to him; for now I know that you fear God, since you have not withheld your son, your only son, from Me".
Abraham passed the test [Hebrews 11:17] and
Hebrews 11:18
"In Isaac your seed shall be called".
Isaac, the true son remained. Remained forever in that he was not cast out. "not cast out" -
Romans 4:13-22
"For the promise that he would be the heir of the world was not to Abraham or to his seed through the law,". 16"Abraham who is the father of us all".
God's promises to His family of faith remain forever.
"Servant" represents: works of law i.e. Sarah's suggestion to involve Hagar [Gen 16:2]/ being cast out.
"Son" represents: faith, not law, Abraham, the true seed remaining.