To those who believe in the Father begetting a Son, there is no problem with this word, but for the Trinitarian, there is a big problem.   In fact, some Adventists become very agitated over the suggestion, despite texts of Scripture to the contrary.

For instance, the following Bible verse.   “But I would have you know, that the head of every man is Christ;  and the head of the woman is the man;  and the head of Christ is God.” 
1 Corinthians 11:3.  No one has any problems with Christ being the head of every man, or that the man is the head of the woman, but that Christ has God as His head is not acceptable.

It is certainly difficult for the Trinitarian, as the word ‘God’ means God the Father, God the Son and God the Holy Ghost, so the text does not ready make sense outside of the incarnation.

Most will accept a mutually accepted subordination by Christ to His Father while living on this earth, and believe His words only apply in that situation, such as, “The Father is greater than I.” 
John 14:28. 

A debate on the subject began in 2016, by Conservative Evangelicals on the “eternal functional subordination (EFS) of the Son.”   At the centre of this dispute is the question of how to understand Scriptural teaching regarding the nature of the Son’s eternal relationship to the Father.   Is the obedience of the Son to the Father limited merely to the incarnation, or does it also extend to the Son’s eternal relationship with the Father?

To quote a very small portion.  “The Trinitarian teaching of the church fathers plays a central role in this dispute.  Proponents and opponents of EFS accuse one another of ‘tampering with the Trinity’, and they appeal to past theologians to substantiate (or deny) this claim.”

One of the theologians of appeal is Augustine of Hippo
(AD354-430)“In turning to Augustine, one draws upon what is arguably the most representative version of trinitarian doctrine in the history of the church among Catholics and Protestants.”  Augustine discusses the divine relations from an “intra-trinitarian standpoint.”   The Father, Son, and Holy Spirit exist in an “inseparably equality of one substance”,  and because they “are of one and the same substance or essence”, “no inequality may exist among them.”  

The debate asks other questions, such as “if the divine persons possess one nature, in what sense, and on what basis, are they distinct?”  Augustine’s answer is that the “real distinctions exist… (and these) are grounded in relations of origin. Because the Father has begotten the Son, the Father is not the Son. Because the Son is begotten by the Father, the Son is not the Father.”

Augustine was not the first to give this answer, but he further enlarges on it as follows: “First the generation of the Son is incorporeal and should not be understood in the manner of human generation.  (Incorporeal – adjective -- not composed of matter; having no material existence.  Synonyms – intangible, non-material, non-physical)   Second, the Father ‘timelessly’ (eternally) begot (sic).”  Thus, the generation of the Son is eternal.  “Third, the Son is begotten by the Father in an equality of nature. Through generation the Son receives the ‘life’ – that is, nature or substance – of the Father… the life of the Father begetting him is co-eternal with the life of the Father who gave it.”  

He also suggested that the divine persons “act ‘inseparably’.”  Anti-Nicenes argued that the “distinct activity of the Father, Son and Holy Spirit indicated that the divine persons were separate beings, with the Father being superior."  In response, pro-Nicenes argued that Scripture shows the activity of the divine persons to be one (i.e. all three persons are involved in acts of creation, providence, and redemption).  

Augustine explained that acting inseparably means “all three persons are involved in every action of creation, providence and redemption… while it was only the Son who became incarnate, the incarnation of the Son was the inseparable work of Father, Son, and Holy Spirit… they share one will and execute one power.”    

This church father is in no way unique in his belief.  Gregory of Nyssa’s account is virtually identical, as is that of Athanasius.   This latter ‘Nicene father’ stated, “The Trinity is consistent in itself, indivisible in nature, and its activity is one.  The Father does all things through the Word in the Holy Spirit;  and thus the unity of the Holy Trinity is preserved; and thus there is preached in the Church one God, ‘who is over all, and through all, and in all’.  He is over all as Father, as beginning, as source;  and through all, through the Word;  and in all, in the Holy Spirit.”

Thomas Aquinas said on the other hand, “As the divine nature, although common to the three Persons, still belongs to them in a kind of order, inasmuch as the Son receives the divine nature from the Father, and the Holy Ghost from them both:  so also likewise the power of creation, whilst common to the three Persons, belongs to them in a kind of order.  For the Son receives it from the Father and the Holy Ghost from them both.”

Another question was:  How did the Father send the Son?   This was asked in the context of inseparable operation.   John Owens, who is on the Evangelical side said, “Did he tell him to come, giving him an order he complied with by coming, or did he ask him to, or did he merely suggest it?”  His conclusion was that as the Son is the Word, the Father “sent him by a word… Hence it is by the Father and the Son that the Son was sent, because the Son is the Father’s Word.”   But this idea is believed to undermine Augustine. 

One conclusion in the words of John Owens is that “Scripture does not reveal that the Son is somehow eternally subordinate to the Father…  but simply reveals that the Son is eternally from the Father.” (i.e eternal generation)

And so the debate continued. 

Thankfully there is no such debate in non-trinitarian circles, at least in this area.  

Two texts that speak of the subordination of the Son to the Father are related to the incarnation.

“I can of mine own self do nothing: as I hear, I judge:  and my judgment is just;  because I seek not mine own will, but the will of the Father which hath set me.” 
John 5:30.   This does no necessarily mean that Christ can literally do nothing on His own, but that He chooses to do nothing except the will of the Father.  In saying this, it doesn’t mean Christ did not need the power of His Father to overcome temptation.

“O My father, if it be possible, let this cup pass from me:  nevertheless not as I will, but as thou wilt.” 
Matthew 26:39.

Three verses are recorded where Jesus says, “My God”, which certainly speak of subordination to a superior.   One is on the cross where Jesus says, "My God, My God, why hast thou forsaken me.”
Mark 15:34.   The next two are after the resurrection.   Jesus meets Mary in the garden and says to her, “Touch me not;  for I am not yet ascended to my Father:  but go to my brethren, and say unto them, I ascend unto My Father, and your Father;  and to my God, and your God.” John 20:17. 

The third is when John is in vision.  Jesus says to the church of Philadelphia, “Him that overcometh will I make a pillar in the temple of my God, and he shall go no more out:  and I will write upon him the name of my God, and the name of the city of my God, which is new Jerusalem, which cometh down out of heaven from my God:  and I will write upon him my new name.”
 Revelation 3:12.    Four times Jesus is claiming  – My God.

Is God the Father --  the God of His Son?   We may not have thought of it if we had not read the words of Scripture, but we have to accept them, not only because they are in the Bible, but because they are words of Jesus.

Our prophet tells us that “God is the Father of Christ; Christ is the Son of God. To Christ has been given an exalted position. He has been made equal with the Father. All the counsels of God are opened to His Son.”   
8T 268.

God the Father gave His Son authority to be the Commander of the angels, to be the only other person in heaven who could enter the divine counsels.    
During Lucifer’s defection, the Father publicly proclaimed His Son as equal with Himself.   “Before the assembled inhabitants of heaven the King declared that none but Christ, the Only Begotten of God, could fully enter into His purposes, and to Him it was committed to execute the mighty counsels of His will….The exaltation of the Son of God as equal with the Father was represented as an injustice to Lucifer, who, it was claimed, was also entitled to reverence and honor… There had been no change in the position or authority of Christ. Lucifer's envy and misrepresentation and his claims to equality with Christ had made necessary a statement of the true position of the Son of God; but this had been the same from the beginning.” 
PP 36.37.   Satan coveted the “glory with which the infinite Father had invested His Son…”  PP 35.

“He who was made equal with God bore the sin of the transgressor, and thereby made a channel whereby the love of God could be communicated to a fallen world, and his grace and power imparted to those who came to Christ in penitence for their sin.” 
ST. February 5. 1894.

Jesus could have remained in heaven receiving the homage of all created beings, but “He chose to give back the scepter into the Father's hands, and to step down from the throne of the universe, that He might bring light to the benighted, and life to the perishing.” 
DA 22.   This implies that Jesus had been given the sceptre in the first place by His Father. 

These inspired statements make it clear that God’s Son, although born a divine Son, was given authority to co-rule the universe.   In this rulership He would “carry out His (Father’s) will and His purposes, but would do nothing of Himself alone.  The Father’s will would be fulfilled in Him.” 
LHU 18.   Again ‘do nothing of himself’ means refusing to work according to His own plans and ideas.  He would always obey the Father’s will.   The Son “would not seek power or exaltation for Himself contrary to God’s plan, but would exalt the Father’s glory and execute His purposes of beneficence and love.”  PP 36.   The Son was “one in power and authority with the Father.”  Ibid.  

According to Seventh-day Adventist theologians, subordination of the Son is not to be seen in an “ontological sense”
(The dictionary says ontological means, ‘branch of metaphysics dealing with the essence of being’)

Quoting Adventist Trinitarian thoughts on John 14:31, 10:18, 12:14-28, the handbook says,  “These statements clearly testify to the existence of a relation of subordination between God the Son and God the Father.  The subordination expressed in these texts must not be understood in an ontological sense, as if the reality of God the Son were dependent on the reality of God the Father.  The Biblical idea of the subordination of God the Son to God the Father belongs, not to the inner structure of divine reality, but rather to the sphere of the accomplishment or the plan of salvation.”
Doctrine of God p126, quoted in  the SDA Handbook of SDA Theology.  Vol 12. SDA BC.  Addition to 27 Fundamentals.

Again, this time relating to Philippians 2:8 and Hebrews 5:8.  “… statements that imply the subordination of God the Son to God the Father (are) to be understood as a result of His incarnation, the expression of obedience to the Father without the subordination of the Incarnation itself would not have reached its salvific purpose.” 
Ibid 126.

The Bible’s message and our prophet’s words are precise.   “To Christ, and to Christ alone, is given the right of authority over all things.” 
TDG 297.

Probably the greatest evidence for subordination, apart from the fact that Christ is the Son of the living God, which of itself denotes at least some subordination, we have clear evidence in the following verses.

“Then cometh the end, when he shall have delivered up the kingdom to God, even the Father;  when he shall have put down all rule and all authority and power. For he must reign, till he hath put all enemies under his feet.  The last enemy that shall be destroyed is death.  For he hath put all things under his feet.   And when all things shall be subdued unto him then shall the Son also himself be subject unto him that put all things under him that God may be all in all.” 
1 Corinthians 15:24-28.

To make it a little clearer, paraphrased by me.
  “Then cometh the end, when Christ shall have delivered up the kingdom to God, even the Father;  when Christ shall have put down all rule and all authority and power.  For Christ must reign, till the Father hath put all enemies under Christ’s feet. The last enemy that shall be destroyed is death.  For the Father hath put all things under His Son’s feet.   And when all things shall be subdued unto the Father, then shall the Son also Himself be subject unto the One who put all things under His feet, that God the Father may be all in all.”  1 Corinthians 15:24-28.   (Ps 8:5.6. Heb 2:8. Eph 1:22.)

Subordination doesn’t mean inferiority, but strength of character in the person willing to obey with a loving heart of faith.   That was Christ, God’s beloved Son.