What additional nature did the Son take upon Himself when came to earth? Paul explains it this way:

‘Have this attitude in yourselves which was also in Christ Jesus, 6 who, although He existed in the form of God, did not regard equality with God a thing to be grasped, 7 but emptied Himself, taking the form of a bond-servant, and being made in the likeness of men. 8 Being found in appearance as a man, He humbled Himself by becoming obedient to the point of death, even death on a cross. 9 For this reason also, God highly exalted Him, and bestowed on Him the name which is above every name, 10 so that at the name of Jesus every knee will bow, of those who are in heaven and on earth and under the earth, 11 and that every tongue will confess that Jesus Christ is Lord, to the glory of God the Father. (Philippians 2:5-11)

Notice the truths that Philippians 2:5-11 states about Jesus. We will look at the passage verse-by-verse:

Have this attitude in yourselves which was also in Christ Jesus. Here we are told that the same humble, condescending, benevolent, disinterested, self-denying disposition be in us which was also in Christ Jesus.

Who, although He existed in the form of God. In the form of God, describes our Lord’s essential, and therefore eternal, being in the true nature of God, while the “taking on Him the form of a servant” as we will soon see refers to His voluntary assumption of the true nature of man.

Did not regard equality with God a thing to be grasped. The Bible says Jesus did not ‘consider EQUALITY with God’ to be grasped, utilized or used to his advantage. Jesus did not regard his equality with God as an object of solicitous desire; that is, though he was fully God and equally divine with the Father, He did not eagerly seek to retain or grasp on to this equality for his own advantage, but voluntarily took on himself a humble condition – even that of a servant. Because Christ was God, He could have taken advantage of His Godhood, glory, and honor and stayed in heaven, and ignored sinful humanity. No! He did not take advantage of His Godhood or equality with God. By the way, why would Jesus even consider EQUALITY with God unless He was EQUAL? How can Christ’s decision NOT to grasp at “equality” with God at Philippians 2:5-7 be an example of humility if Jesus was not already entitled to claim equality? That is because Jesus is divine as the Father is divine, and is equal to the Father in divine nature, essence, substance.

But emptied Himself. He emptied himself; not His divinity or deity, but of its manifestation, its glory.  He emptied himself voluntarily of the “glory which He had with the Father before the world was” (John 17:5) How?

Taking the form of a bond-servant, and being made in the likeness of men.  Now the Son, is not just God, but he also takes on humanity, THUS becoming also the Son of Man. He is Son of God and Son of Man.  Thus, He becomes this unique God-Man. It would have been an infinite humiliation for God of glory to have assumed humanity; but our God went beyond this. Not only did he take on human likeness, but also the very nature of a humble servant. The Son who created even angels, now was “made lower than the angels” (Hebrews 2:9).

Being found in appearance as a man, He humbled Himself by becoming obedient to the point of death, even death on a cross. Aftermanifestation of Himself to the world in all the weakness of humanity, meaning He had not only laid aside the symbols of His divine glory, and become a man; but when he was a man, he humbled himself, and He obeyed even when His obedience terminated in death, which was a long lingering, painful, humiliating death of the cross. ^“For even the Son of Man did not come to be served, but to serve, and to give his life as a ransom for many.” (Mark 10:45).

For this reason also, God highly exalted Him. “For this reason” meaning because the Son who did not hold onto his divinity, instead, voluntarily laid aside his glory and became this new God-Man,and died on the Cross for humanity, Father now exalts the Son back to the highest place and highest glory in response to the Son’s humility and achievement.Christ humbled himself, and He is not going to exalt himself. That would be prideful and that is not the nature or the character of God. ‘For those who exalt themselves will be humbled, and those who humble themselves will be exalted’ (Matthew 23:12). Instead it is God the Father who exalts Jesus, now note this again, not as ‘God’ (which was Jesus’ pre-existence before He came to this earth), but as this humble God-Man, who was humiliated at the cross, but was resurrected defeating the power of death. Therefore, after His resurrection, Jesus is being declared or made “better than angels” (Hebrews 1:4), in contrast to His being “made lower than the angels for a little while” while on earth (Heb 2:9).

And bestowed on Him the name which is above every name. The name given is not the name Jesus, which was given him at his circumcision, but the name Jehovah (Philippians 2:11), which was indeed his before he became Messiah, and is given now to Jesus as not as God (which He existed from all eternity), but now as this God-Man, who humbled himself, added human nature to divine nature, died and rose again. The dignity and glory is expressed by “above every name”.

Notice a similar thing happens to Christ’s title as the Son of God:

‘Who was declared the Son of God with power according to the Spirit of holiness by the resurrection from the dead, Jesus Christ our Lord’ (Romans 1:4).

Why would Christ be appointed or declared to be Son of God at the resurrection if he was already the Son of God before? The declaration is a confirmation of the resurrected divine Son of God that he truly is divine. When a king was enthroned in the Old Testament, there was an acclamation or declaration that he was formally taking up his title and inheritance which had been his by birth. Similarly, Christ our King is taking up his name, title as Jehovah, which is His by inheritance, in a newer sense as the victorious God-Man at His ascension to the Father.

So that at the name of Jesus every knee will bow, of those who are in heaven and on earth and under the earth. The knee should bow, or bend, in token of honor, or worship at the name of Jesus. Only to Jehovah we must bow. If you still have any doubts if Jesus is and has been the Almighty Jehovah, notice this verse, speaking of the one true Almighty God, Isaiah prophesied: ‘Turn to me and be saved, all you ends of the earth; for I am God, and there is no other. By myself I have worn, my mouth has uttered in all integrity a word that will not be revoked: Before me every knee will bow; by me every tongue will swear’ (Isaiah 45:22-23).

Jehovah God says that there is no God beside Him, and that every knee will bow to Him only, and every tongue will swear that He is God. Who is the Lord God that every knee will bow?

And that every tongue will confess that Jesus Christ is Lord. What is the name above every name? The word “Lord” is the word constantly used in the Greek translation of the Hebrew Old Testament to refer to Jehovah. The context would suggest that meaning here, for the worship paid is obviously to God alone. Every true believer will acknowledge that Jesus is Jehovah Almighty.

To the glory of God the Father. The acknowledgment of the glory of Christ is the acknowledgment of the glory of the Father. “That all may honor the Son just as they honor the Father. Whoever does not honor the Son does not honor the Father, who sent him” (John 5:23).

Hence, before Jesus came to this world, the Bible teaches us that He existed continually as the eternal Son of God (or even God the Son), but when He came into this World some 2000 years ago, He was made flesh through a virgin, made lower than angels, meaning he became a human being to become our messiah, our sacrifice, the Son of Man, and High priest and more. So, remember, the Word was not always ‘flesh’ before entering the human race some 2000 years ago. Neither was the ‘Word’ the Messiah or Christ in His eternal existence. “Christ” comes from the Greek word Christos, meaning “anointed one” or “chosen one.” What a God! What a Savior! To say that the Son was not equal with God, or that the Son was not fully God, or not the God of the Old Testament is an insult to our Lord and the truth of Scripture.

See:

The Only Begotten Son (John 1:1-18)

Father gave the Son to have life in Himself? (John 5:1-27)