See below for a more precise definition of the question.
Two Views among Evangelicals
Ted Peters says that if anything, contemporary mainline Protestant and Roman Catholic trinitarian thinking is “antisubordinationist.” (God as Trinity (Louisville: Westminster, 1993), p. 45.) But Kevin Giles, in an article in The Academic Journal of CBE International, stated:
“Paradoxically … many evangelical theologians have been moving in the opposite direction. Since the 1980s, evangelicals wishing to uphold the idea male headship … have been arguing that the Son is eternally subordinated to the Father.”
"Conservative evangelicals who speak of the eternal subordination of the Son quote in support Paul’s assertion that God the Father is the “head of Christ” just as “man is the head of woman” (1 Cor 11:3), and the texts that speak of the Son being “sent” by the Father (John 4:34, 5:30 etc.), and obeying the Father (Rom 5:18-19; Heb 5:8).
Giles, on the other hand, claims that the Bible writers present the Son as equal with the Father:
“They frequently associated the Father, Son, and Spirit together, implying their equality (cf. Matt 28:19; 1 Cor 12:4-6; 2 Cor 13:13; Eph 4:4-6; etc.), and on occasions spoke of Jesus as Theos (John 1:1, 20:28; Rom 9:5; Heb 1:8), calling him “the Lord” (the title for Yahweh used in the Greek OT) some two hundred times.”
Can the Bible answer this question?
However, Giles implies that this debate, whether the Son is subordinate to the Father or not, cannot be resolved from the Bible alone and that we must rely on “tradition:”
“If there were no way to settle this debate over the interpretation of the Bible we would have a stalemate. Each side could simply go on quoting their proof texts and no resolution would be possible. But this is not the case. Evangelicals … are in complete agreement that “tradition”—understood as how the scriptures have been understood by the best of theologians across the centuries—is a good guide to the proper interpretation of scripture: it is a secondary authority.”
Gotquestions, another conservative protestant site, claims that the Bible is able to provide the answer. Using language that is similar to the Athanasian Creed, it states:
The Bible teaches that the Father is God, that Jesus is God, and that the Holy Spirit is God. The Bible also teaches that there is only one God.
The Question
(a) The Trinity doctrine teaches that the Son is equal with the Father. What are the main texts and principles in the New Testament that are used to prove the equality of the Son to the Father and how do non-trinitarians show that these texts do not prove equality? (b) The Trinity doctrine teaches that the Person of the Son is ontologically equal but functionally subordinate to the Father. What are the main texts and principles in the New Testament that support eternal functional subordination and how would non-trinitarians show that eternal functional subordination is inconsistent with the Trinity doctrine?
Eternal Subordination
As Giles indicated:
“All accept that the Son was for a limited period (temporally) subordinated in the incarnation. What is in dispute is whether or not the Son is subordinated in the eternal or immanent Trinity in his being/nature/person and/or work/operation/function.”
So, I am particularly interested in indications that the Son was subordinate to the Father before He “became flesh” and after His ascension.
Role vs Being Subordination
Giles distinguishes between “eternal subordination in role/function” and “subordination in person or being,” but also states that, if the Son, in “eternity” is subordinate in His “role/function,” then He is also subordinate in His “being:”
“Most speak only of an eternal subordination in role/function for the Son. However, some evangelicals honestly admit that eternal role subordination by necessity implies subordination in person or being.”
In note 4 of his article, Giles states that this distinction ”is entirely novel. It has no historical antecedents. Previously the argument has been eternal subordination in being/nature/essence and work/operation/function are two sides of one coin.”
Furthermore, the Bible does not explain the relationship between the Father and Son in terms of substance or being. Nevertheless, since no Trinitarian will be convinced by an answer that avoids this Trinitarian defense, the answer must address the distinction between Role and Being Subordination.
Catholic Christians
Perhaps this is not a question that will interest Catholic Christians, since they rely on tradition to a greater extent. On the other hand, for that same reason, compared to protestants that are subject to the demands of Sola Scriptura, Catholic Christians sometimes can afford to be more honest with respect to the meaning of the Biblical text.