Phil 2:5 You should have the same attitude toward one another that Christ Jesus had,
2:6  who though he existed in the form of God
did not regard equality with God
as something to be grasped,
2:7 but emptied himself
by taking on the form of a slave,
by looking like other men,
and by sharing in human nature.

This text is relevant to discussions about the Eternal Submission of the Son.

The word ‘regard’ (ἡγησατο) potentially sheds light on the thought processes of the Son in eternity past.  Routley quotes Robert Letham:

‘His decision to [empty himself] was made prior to his doing it. His determination not to exploit his true and real status for his own advantage was made in eternity. His self-emptying on earth flowed from his refusal to pursue self-interest in eternity. His human obedience reflects his divine submission.’

Verses 5-11 appear to track a chronological progression, from Christ’s preincarnate glory to his resurrected and ascended glory.  In eternity past, when Christ ‘existed in the form of God’, he ‘did not regard equality with God
as something to be grasped’.  This expression has, of course, been extensively debated.  But we note that it does not make sense for Christ to ‘grasp’ what he already possessed (namely, equality with God).  As Melick suggests, the meaning may well be that Christ ‘did not regard equality with God as something to be used to his own advantage.’  Wallace, in his Greek Grammar, says that the Son did not attempt to ‘outrank’ the Father (cf. Jn 14:28).

Routley comments:

Philippians 2:6, then, demonstrates the eternal Son’s refusal to use his own deity selfishly, and instead his willingly taking humanity to himself for the good of others. It presents Christ’s mental thought process as one where the Son of God, fully God himself, freely and voluntarily emptied himself through becoming incarnate.

Letham (quoted by Routley) agrees:

The Son’s self-emptying, his seeking the interests of the others in his incarnate ministry, is not alien to who God is. This is what God is like. The Son freely chose to become man. He did not regard his equality with God as something to be exploited. His actions in the gospels mirrored his determination in eternity; they were far from incongruous.

In fact, Routley suggests, the submission of the Son to the authority of the Father is seen in this passage in several ways:

‘In the preincarnate determination of the Son to empty himself through the taking of humanity.’  This is consistent with those other NT passages which speak of the Father ‘sending’ the Son.

‘In the Son’s being obedient to death, even death on a cross (v. 8).’  Lest we posit a dangerous and unbiblical disjunction within the person of Christ, we must assume that ‘obedience demonstrated in the incarnation flows out of eternal submission and obedience.’

‘God the Father’s exaltation of Christ to the highest position, with the highest name, shows the Father’s primacy in power in Paul’s thinking and the Son’s submission to that power.’  The Father’s authority in thus exalting his Son is underlined in v11 (‘…to the glory of God the Father’).

Routley concludes:

Jesus’ exaltation is ultimately for the Father’s glory and not his own, driving home Paul’s point of having an attitude of humility that looks out for the interests of others. Throughout his preincarnate, incarnate, and glorified existence, the Son looks out for the interests of God the Father and of humanity over and above his own interests.

Routley, Jonathan J. Eternal Submission: A Biblical and Theological Examination (pp. 43-47).

Beth Felker Jones argues from this passage that Christ’s submission belongs only to his incarnate state:

‘In the form of God’ = ‘being in very nature God’ (NIV).  Refers to his pre-existent state, confirming his divinity.

‘He humbled himself by becoming obedient’ (NIV) – he became obedient (when he became incarnate)

‘He did not consider equality with God something to be used to his own advantage’ (NIV) – he had always been equal with God.  But he did not exploit this equality.  Rather, he chose to act as a genuine human being, in a relationship of humble obedience towards his Father.  Satan tempted Jesus to exploit his royal prerogatives in order to establish a worldly kingdom, but Jesus refused to do so.  Jesus therefore becomes a model and pattern for a genuine human relationship with God.

When Jesus says, “The Father is greater than I” (Jn 14:28), he is speaking from within the story of his incarnation.

Since Jesus has two natures – divine and human – so also he has two wills – divine and human.  As a man, he shrank from the prospect of the Cross.  And so he prays, as all humans must, “Not my will but yours be done” (Lk 22:42).  But as the Son, his will and the Father’s are indivisible: they both want the same thing.

In conclusion:

‘It’s true that Jesus shares co-eternal unity with the Father in the Spirit—a unity in which there can be no subordination or it wouldn’t be the true unity that it is.

At the exact same time—because he has become human for love of us— it is true that Jesus submits to the Father in the Spirit, because in conforming his humanity to the Father’s will, he invites us to be so transformed.’