This is a very special passage that comes to a new reality when Jesus appears - in ways hardly imagined by the people of Isaiah's day or any other time before God's mystery was made known.
Jesus IS the word of God - His logos who accomplishes what God sent him to do.
Jesus is sent to do vital work which culminates in his obedient death on a cross. He was of course sinless and holy from birth and was always, since Gen 3, the plan of God for salvation of creation. The second and last Adam who would right what the first Adam had, under duress, failed at - upholding God's will.
Jesus, as God's word enfleshed, is now a living human being. This is a totally new endeavour of God. Jesus is not a robot who obeys every 'command'. He is a man with his own will, with his own life to live in the thick of evil - tempted by the devil himself.
He must suffer and learn obedience through that suffering so that in every matter, he puts God's will before his own. There were some difficult moments when it was very hard - seemingly impossible. Why did he obey to the bitter end? Because of love, respect, worship... yes Jesus has a God, the same God we do.
2 Cor 1:3 Blessed be the God and Father of our Lord Jesus Christ, the Father of compassion and the God of all comfort, 11:31, Eph 1:3, Col 1:3, Rom 1:7, 15:6, 1 Pet 1:3
John 20:17 Jesus said to her, "Stop clinging to Me, for I have not yet ascended to the Father; but go to My brethren and say to them, 'I ascend to My Father and your Father, and My God and your God.'"
I'm hardly sure what the OP has in mind. "God fully becoming His word', scripture says Jesus was filled with God, he was the image, the form - none of these make him God.
Let's briefly outline the important parts of this 'Word sent out'.
- Jesus is the word made flesh - he had to be tempted as the first Adam was also tempted by evil. He also had the potential for sin, and could obviously die. When God says He gave His 'only' son - there is no mention anywhere of a pre-existing son who was immortal and equal to God.
- Jesus relied on his God for everything he needed to survive the arduous journey to the cross. He had nothing more than any other man except one thing - he was without sin to begin with. This must radically change the focus of a human compared to one corrupted by sin and selfishness.
John 5:30 I can do nothing on my own. As I hear, I judge, and my judgment is just, because I seek not my own will but the will of him who sent me. also John 5:19 and others.
Heb 1:2 in these last days has spoken to us in His son, whom He appointed heir of all things, through whom also He made the ages (not world or universe)
God making God heir is obviously quite silly.
He is made Lord and Christ Acts 2:36 Made by who? God. God making His amazing son, who served Him perfectly until a most hideous death and
reconciling all creation to Him was worthy of such glory - along with being exalted above all others except God of course. How then could Jesus be 'equal', when his own words specify consistently that his Father and God is greater in many ways than he. John 14:28
The Father gave Jesus life - in the flesh through Mary and in spirit when He raised him from the dead and took him to 'heaven'. God already has life - this can never not be true. Jesus does not have true life until the Father gave it to him, making him immortal at last. He can now give this life to others, raising them from the dead. John 5:28
For Christ ... having been put to death in the flesh, but made alive in the spirit. 1 Pet 3:18
For just as the Father has life in Himself, so He gave to the son also to have life in himself John 5:26
Jesus, as God's logos, is not merely a royal decree that gets done as commanded. Jesus has to choose to do God's will, to obey the royal decree in honour and respect and love.
Jesus had perfect free will. Free will is not free will if there is deception. If there is no clear understanding of the consequences of both sides of the matter before a choice is made - they are not exercising free will. Jesus was uncluttered by deception and corruption caused by sin. He chose God - not with his own will only, as that sometimes differed from the Father. He chose by the help of God's spirit, given to him at baptism.
During the days of Jesus’ earthly life, he offered up prayers and petitions with loud cries and tears to the One who could save him from death, and he was heard because of his reverence. Heb 5:7
His whole life was lived by the power of God in him - definitely not by being God. He had to suppress his will for the Father’s at every moment, clearly some moments were very stressful.
When he had accomplished his mission and cried the last words, "It is finished!" he was dead for three days until the Father raised him and took him to His side. He did not 'return there'. While there are several verses that say this, John 16:5,28, 13:1,3, 20:17, 14:28, the words 'returning' or 'going back' have been added to the text to support the Jesus is God dogma.
Jesus fulfilled God's purposes perfectly. It wasn't easy, it was very hard, but evil and death is now defeated for ever. Not by power alone, but by the power of love.
For it was the Father’s good pleasure for all the fullness to dwell in him, 20 and through him to reconcile all things to Himself, whether things on earth or things in heaven, having made peace through the blood of his cross. Col 1:19-20