It’s a beautiful question for it is raw and sincere
Let’s first assess the components
- All things
- The one who upholds the ages/universe
- His temporal state as a human
The context of the question is in The book of Hebrews, therefore there are clues in the surrounding verses.
“He is the radiance of the glory of God and the exact imprint of his nature, and he upholds the universe by the word of his power δύναμις. After making purification for sins, he sat down at the right hand of the Majesty on high,”
The Son became the Son on day one of Creation before anything existed. Otherwise the last part of v2 makes no sense and this fits into psalm 2.
means all things Created. God being uncreated. Therefore this means time, space, natural laws, supernatural laws, earthly bodies, heavenly bodies, earth and the heavens, visible or invisible.
“For by him all things were created, in heaven and on earth, visible and invisible, whether thrones or dominions or rulers or authorities—all things were created through him and for him.”
The one who upholds the ages/universe
In Hebrew understanding the Mimra concept is from the Aramaic Old Testament expository known as Targum Onquelos. It is the direct equivalent to the Greek logos used by John in John 1:1. The mimra was with God before Creation. It was the Word of God, it was God. If the mimra stopped existing for a split second, and reappeared the next, everything that was, would disappear and not reappear. For everything exists because of the mimra. It remains through the mimra.
His temporal state as a human
The one we know as Jesus, aka Yeshua, aka the Son, existed before Creation according to John 17:5,24. To exist before Creation means you had to be God. Nothing existed before Creation, for there was no time, space to exist in before that, with the exception of God. And God is echad Deuteronomy 6:4 meaning united, that is three persons.
God is Spirit John 4:24 but a Spirit can take on a body, be it a heavenly body or an earthly body. When Jesus became a human, the Holy Spirit placed the kenosised (the voluntarily nullified/‘switched off’ divine attributes) spirit of the Son and placed it inside the baby inside virgin Mary
How could Christ uphold the universe as a helpless babe and also after he had died before the resurrection
The answer is rather simple He the Word NEVER ceased from existence. Sure as a human He was murdered but the spirit of the Son that inhabited the body of the human we know as Jesus from Nazareth was not killed
He didn’t come into existence at the incarnation and didn’t phase out at the crucifixion. He remained full of POWER δύναμις
“who will transform our lowly body to be like his glorious body, by the power δύναμις that enables him even to subject all things to himself.”
And now that He has redeemed Creation and regained legal rights to His own Creation He has all the ἐξουσία authority and the δύναμις power
“All things were made through him, and without him was not any thing made that was made.”
And the Word, the mimra, the begotten Son of psalm 2 decided to come live as a man
“And the Word became flesh and dwelt among us, and we have seen his glory, glory as of the only Son from the Father, full of grace and truth.”
Partly explains why He called Himself the son of man, it was an exciting new experience for Him, He could now experience life as a human
“For we do not have a high priest who is unable to sympathize with our weaknesses, but one who in every respect has been tempted as we are, yet without sin.”
He is the Word and the Word is right there in the Hebrew text in Genesis 1:1
בראשׁית ברא אלהים את השׁמים ואת הארץ
In beginning created God the Word, the heavens, the same Word the earth
“that their hearts may be encouraged, being knit together in love, to reach all the riches of full assurance of understanding and the knowledge of God’s mystery, which is Christ, in whom are hidden all the treasures of wisdom and knowledge.”