Jesus was a man, and who, as a man was under the Law expected to be obedient to the Law.
You fail to respect this about Jesus and lean more heavily on His Divinity to the exclusion of His humanity.
I would presume that you've never experienced the Person of the Holy Spirit in your walk and appear to me to be man-centered in all your experiences with the Almighty. What is faith but trust. Here, read this:
1 Now faith is the substance of things hoped for, the evidence of things not seen. Hebrews 11:1.
The Greek word is "ὑπόστασις" hypostasis. Faith is the "hypostasis" of things hoped for, the evidence of things not seen. The word is also found here:
3 Who being the brightness of his glory, and the express image of his person, and upholding all things by the word of his power, when he had by himself purged our sins, sat down on the right hand of the Majesty on high;
Hebrews 1:3.
Defined as: [#5287] from a compound of [#5259] (hupo) and [#2476] (histemi); a setting under (support), i.e. (figurative) concrete essence, or abstract assurance (object or subject.)
Was it His humanity that purged our sins or was it His Deity that purged our sins?
Now, why would the translators of the KJV translate the "hypostasis" as [a] "person"? Faith is a Person?
Yes, faith is a Person and that Person is Christ/Messiah/Anointing. Faith-ful (and True) is one of Jesus' Names.
Hypostasis is where we get "Hypostatic" as in Hypostatic Union, the very doctrinal term for Jesus being BOTH God and man. Was it His humanity upholding His Deity; or was it His Deity upholding His humanity? According to you it is His humanity upholding His Deity. But you would be wrong. It is His Deity that was upholding His humanity. Another proof that Jesus' temptation/testing was a proving of His humanity and not His Deity. He was a most unique Person, someone of whom there is no other like Him. Being hungered, walking up the staircase that led to the pinnacle of the Temple and whether to throw Himself down, or observing all the kingdoms of the world [to that date] address His humanity, who He is and the pride of His life. These were not testing His Deity. He knew who He was. At the age of twelve discussing with the priests the things of God He was aware that God was His Father ["My Father's business"], remember?
But I am getting ahead of myself. The thing is that as a man He was expected to function "in all ways" as a man and this included trusting God as God and as His Father. He was tested "in all ways" as a man who is tested being just a man. And as a man He was limited in His knowledge which is why He asked questions in order to ascertain more information in order to proceed as a man would, and this includes faith-ing God, or trusting God and being trusted as a Son. The point being that as a man He was tested as men are tested and this includes having faith in God. If "My God, My God" from the cross doesn't address Jesus as a man instead of, "My Father, My Father" [why hast thou forsaken me] then Jesus was not a man who was "tempted in all ways as we are yet without sin" doesn't speak to you that as a man He is able to succor experience things as a man then He cannot be our Mediator. For we need someone who can understand what a man goes through to be our High Priest to represent us to God, and God, to us. But let me ask you...Jesus was a Carpenter. Did His stepfather, Joseph, teach Him in woodwork or did He immediately have total knowledge of His craft?
16 For verily he took not on him the nature of angels; but he took on him the seed of Abraham.
17 Wherefore in all things it behoved him to be made like unto his brethren, that he might be a merciful and faithful high priest in things pertaining to God, to make reconciliation for the sins of the people.
18 For in that he himself hath suffered being tempted, he is able to succour them that are tempted.
Hebrews 2:16–18.
Maybe you see Jesus as 60-40, or 70-30? Seventy as Deity/Divine and thirty being man? Is that the formula? Or was He 100-100 [%] fully man and fully God? He was and is the seed of Abraham and as such can be claimed as a son of Abraham. So, what measure was His humanity against His Deity? I suffer, He suffered. I get hungry, He got hungry.
34 And saith unto them, My soul is exceeding sorrowful unto death: tarry ye here, and watch. Mark 14:34.
In His prayers to God it was necessary for Him to
5 That your faith should not stand in the wisdom of men, but in the power of God. 1 Corinthians 2:4–5.
There is a faith that is of the wisdom of men - [which is not faith at all] - and there is a faith that is the power of God. Which one is given of God? Everything about salvation is from God. Everything about salvation originates with God and not men. Like Lazarus, men are dead in trespasses and sin. Lazarus could not exercise any faith to be resurrected or made alive. He lay in the tomb four days, and it could have been five or six days, or a month, the point is that faith is from above, not below, and faith cannot be exercised by dead men walking. It, or should I say, HE is [the] gift of God.
Does this apply to Jesus?
6 But without faith it is impossible to please him: for he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him. Hebrews 11:6.
But God Himself says, "This is my Beloved Son in whom I am well pleased."
So, Jesus as a man had to have faith in God as God and in His Father as His Father. And when Jesus prayed, He prayed the will of God, and by being in one accord with the Father was the key to answered prayer. Did He pray for twelve legions of angels? No, He didn't. His purpose was not to suffer the cross, but He welcomed it. Several times He said He was going to Jerusalem to die. His "face" was set towards it. So, there is a faith that is measly and deficient and that is the faith of mere mortals, mere men. And then there is a faith that is from God. That is the faith that moves 'mountains.'
Is there any passage in Scripture that says that men's faith is like a mustard seed that grows and in whose branches the birds of heaven lodge? Or is it Christ's faith that is likened to such a tree? My faith might seek this or that, but I have experienced His faith that accomplished what it set out to do. Many times, this has happened to me. And when this faith was given to me and through whom it came, I received what it sought without fail. This is the faith Jesus had, and I had the same faith - BUT it was given to me to experience, and it didn't come from me for I recognize not only His Voice and His Word, but His Presence that accompanied it. Faith is Christ. And Christ is faith. And it was His faith that God and Father honored which enabled Him to live and to save that which was lost. And that which was lost are all those whose names were written in by God in the book of life of the lamb.
So, yes, Jesus had faith. And it is His faith through which anyone is saved.