At least since Plato (pronounced "Play-Doh") Western philosophers have been discussing what constitutes "perfection":
http://plato.stanford.edu/entries/perfectionism-moral/#TwoVerPer
Philosophic ideas of perfection have led to the "textbook" list of attributes of God that start with the prefix "omni", such as "omniscient" and "omnipotent":
http://www.theattributesofgod.org/list-of-attributes.html
Among these philosophy supplies the following precept:
Self-Sufficiency of God - God has no needs, cannot improve and does
not change. We, on the other hand, as created beings rely completely
on God for our every breath. [ibid]
So, if God were to learn something new it would reveal that he was not previously "perfect" (in the philosophic definition) and that is unacceptable. This gives logical rise to the Calvinist view that absolutely everything in all eternity, forward and back is an emanation of God's eternal will. He never learns anything at any time because from eternity past he has not changed, improved or admitted to any imperfection, lack, etc.
Trinitarians claim that Jesus has all of the qualities and attributes of the Western philosophers. Therefore it is deemed impossible that Jesus would learn anything, have anything ever out of his absolute control, have any lack, need, or want, etc. Hence the question.
However, it is evident from the scriptures that Jesus is utterly dependent on God at all times and for all things:
Joh 14:10 Do you not believe that I am in the Father and the Father
is in me? The words that I say to you I do not speak on my own
authority, but the Father who dwells in me does his works.
Mar 13:32 "But concerning that day or that hour, no one knows, not
even the angels in heaven, nor the Son, but only the Father.
Mat_27:46 And about the ninth hour Jesus cried with a loud voice,
saying, Eli, Eli, lama sabachthani? that is to say, My God, my God,
why hast thou forsaken me?
Luk 2:52 And Jesus increased in wisdom and in stature and in favor
with God and man.
Luk_23:46 And when Jesus had cried with a loud voice, he said,
Father, into thy hands I commend my spirit: and having said thus, he
gave up the ghost.
So since Jesus is utterly dependent on God, learns and even dies he obviously does not feature the attributes of God and is not God.
To get around this we are told that he temporarily "emptied himself" of his divine attributes (while retaining "divinity" in a more abstract sense) and/or temporarily emptied himself of the prerogative to use his super powers. Yet conversely, in the scriptures, Jesus always confesses that whatever super powers he has he has them from God:
Joh 5:19 So Jesus said to them, "Truly, truly, I say to you, the Son
can do nothing of his own accord, but only what he sees the Father
doing. For whatever the Father does, that the Son does likewise. Joh
5:20 For the Father loves the Son and shows him all that he himself
is doing. And greater works than these will he show him, so that you
may marvel. Joh 5:21 For as the Father raises the dead and gives them
life, so also the Son gives life to whom he will. Joh 5:22 The Father
judges no one, but has given all judgment to the Son, Joh 5:23 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. Joh 5:24 Truly,
truly, I say to you, whoever hears my word and believes him who sent
me has eternal life. He does not come into judgment, but has passed
from death to life. Joh 5:25 "Truly, truly, I say to you, an hour is
coming, and is now here, when the dead will hear the voice of the Son
of God, and those who hear will live. Joh 5:26 For as the Father has
life in himself, so he has granted the Son also to have life in
himself. Joh 5:27 And he has given him authority to execute judgment,
because he is the Son of Man. Joh 5:28 Do not marvel at this, for an
hour is coming when all who are in the tombs will hear his voice Joh
5:29 and come out, those who have done good to the resurrection of
life, and those who have done evil to the resurrection of judgment.
Joh 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.
So, the scriptures have no problem with Jesus learning, but Trinitarians have a yuge problem with it.
So in what way does the author of To The Hebrews depict Jesus as not being self-sufficient?:
Self-Sufficiency of God - God has no needs, cannot improve and does
not change. We, on the other hand, as created beings rely completely
on God for our every breath. [ibid]
So obviously Jesus is not God since he is utterly dependent on God for all things, including his every breath:
Rom 6:9 We know that Christ, being raised from the dead, will never die again; death no longer has dominion over him.
That is, God raised him from the dead and freed him from death's dominion over him. Therefore Jesus breathes because of God.
So this segues nicely into the ways that God "perfected" Jesus, per Hebrews:
- he appointed Jesus and raised him from the dead:
Act 17:31 because he has fixed a day on which he will judge the world
in righteousness by a man whom he has appointed; and of this he
has given assurance to all by raising him from the dead."
Heb 5:1 For every high priest chosen from among men is appointed
to act on behalf of men in relation to God, to offer gifts and
sacrifices for sins. Heb 5:4 And no one takes this honor for
himself, but only when called by God, just as Aaron was. Heb 5:5 So
also Christ did not exalt himself to be made a high priest, but was
appointed by him who said to him, "You are my Son, today I have
begotten you"; Heb 5:6 as he says also in another place, "You are a
priest forever, after the order of Melchizedek."
- God beset Jesus with weaknesses:
Heb 5:2 He can deal gently with the ignorant and wayward, since he
himself is beset with weakness.
ISV Heb 2:10 It was fitting that God, for whom and through whom
everything exists, should make the pioneer of their salvation perfect
through suffering as part of his plan to glorify many children, Heb
2:11 because both the one who sanctifies and those who are being
sanctified all have the same Father [εξ ενος]. That is why Jesus is
not ashamed to call them brothers Heb 2:12 when he says, "I will
announce your name to my brothers. I will praise you within the
congregation." Heb 2:13 And again, "I will trust him." And again, "I
am here with the children God has given me." ... Heb 2:17 thereby
becoming like his brothers in every way, so that he could be a
merciful and faithful high priest in service to God and could atone
for the people's sins. Heb 2:18 Because he himself suffered when he
was tempted, he is able to help those who are being tempted.
- Jesus was obligated to offer sacrifices for his own sin in addition to that of the People (the Jews) because of his moral vulnerability:
Heb 5:3 Because of this he is obligated to offer sacrifice for his
own sins just as he does for those of the people.
- because of his moral vulnerability he experienced great anguish and relied upon God in a life-or-death struggle against sin and death:
Heb 5:7 As a mortal man, he offered up prayers and appeals with loud
cries and tears to the one [God] who was able to save him from death,
and he was heard because of his devotion to God. Heb 5:8 Son though
he was, he learned obedience through his sufferings Heb 5:9 and,
once made perfect, he became the source of eternal salvation for all
who obey him,
So to answer the question, it is crystal clear that Jesus was a man chosen, ordained, providentially appointed to suffer, utterly dependent and who became a more compassionate person by his moral vulnerability and utter dependence on God. No amount of "workarounds" can change this depiction of a non-divine savior. He underwent a process to improve him by making him more compassionate through suffering.