I'd like to offer another answer because I'm pretty sure user14 believes in Arianism. Arianism is considered a form of Unitarianism, but I believe you're asking for biblical evidence that Yeshua is a man, and not "a god" or a preexisting spiritual entity.
Strictly speaking from a soundness perspective, the gospels say Yeshua is a man. Therefore, the only thing we can be absolutely sure of is that Yeshua is a man. This is the reason why the trinitarian formula necessarily says Yeshua is "fully human" and it is why Arianism falls short.
However, trinitarian theology also says Yeshua is God, but there is not a single verse in the NT that says this. Therefore, where soundness in trinitarianism is concerned, Yeshua is definitely a man- but there is supposedly a hidden gnosis that reveals Yeshua to be God. So as you read this, bear in mind that most of it is actually relevant to trinitarianism.
The following words and phrases are used by trinitarians, as well as many Arians. None of these are in any bible I have ever read:
Jesus is God
Jesus said "I am God"
God became a man
God died (!!!)
Plato and Aristotle
There are many other terms, including the Greek philosophy essential to explaining these terms, but I think you get the idea.
The son of man
In all four gospels, Yeshua refers to himself as "the son of the man" or ὁ υἱὸς τοῦ ἀνθρώπου. Matthew, Mark, and Luke are fairly similar in their accounts of Yeshua's life, and in none of these is Yeshua ever presented as anything other than a man. There are two virgin birth stories in Matthew and Luke which sound nothing alike, but even if the first two chapters of these books are legit, Yeshua is a man and understood to be a man.
When we get to John's gospel, things get a bit "mystical", but John still refers to Yeshua explicitly as a man:
"This is he of whom I said, After me cometh a man which is preferred before me: for he was before me." John 1:30
"John answered and said, A man can receive nothing, except it be given him from heaven." John 3:27
"Come, see a man, which told me all things that ever I did: is not this the Christ?" John 4:29
"Not that any man hath seen the Father, save he which is of God, he hath seen the Father." John 6:46
Book or Acts
The book of Acts also presents Yeshua as a man, as the following verse clearly shows:
"Ye men of Israel, hear these words; Jesus of Nazareth, a man approved of God among you by miracles and wonders and signs, which God did by him in the midst of you, as ye yourselves also know" Acts 2:22
Epistle to the Hebrews
In the epistle to the Hebrews, not only is Yeshua presented as a man, but the author's entire argument rests on this fact. Here is another answer that explains why the Greek word δι' means "because of", even in the genitive. So Hebrews 1:2 says:
"Hath in these last days spoken unto us by [his: not in the Greek] a son, whom he hath appointed heir of all things, by (δι': because of) whom also he made the worlds (ages)."
The ages were not made "by" Yeshua- they were made “because of” him- because he is the reason (logos) for the preparation of man. YHVH is pretty clear about making everything by Himself:
"Thus saith YHVH, thy redeemer, and he that formed thee from the womb, I am YHVH that maketh all things; that stretcheth forth the heavens alone; that spreadeth abroad the earth by myself" Isaiah 44:24
The ages were also not made "through" Yeshua, because that doesn't make any sense. Yeshua was not some sort of "Word-tool" that God used to prepare all things.
The first two chapters of Hebrews is about mankind. The author is arguing that it wasn't angels, or any other divine being, that God made the world for. This is explained in Genesis:
"And God said, Let us make (נַֽעֲשֶׂ֥ה: accomplish; H6213) man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth." Genesis 1:26
This is why the next verse in Hebrews says:
"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 (δι': because of) himself purged our sins, sat down on the right hand of the Majesty on high; Being made so much better than the angels, as he hath by inheritance obtained a more excellent name than they."
The author then goes goes on to explain how the Scriptures prove that God has always favored mankind. He ends his prologue in the next chapter with verses 5-18:
"For unto the angels hath he not put in subjection the world to come, whereof we speak.
But one in a certain place testified, saying, What is man, that thou art mindful of him? or the son of man, that thou visitest him?
Thou madest him a little lower than the angels; thou crownedst him with glory and honour, and didst set him over the works of thy hands:
Thou hast put all things in subjection under his feet. For in that he put all in subjection under him, he left nothing that is not put under him. But now we see not yet all things put under him.
But we see Jesus, who was made a little lower than the angels for the suffering of death, crowned with glory and honour; that he by the grace of God should taste death for every man.
For it became him, for whom are all things, and by (δι': because of) whom are all things, in bringing many sons unto glory, to make the captain of their salvation perfect through sufferings.
For both he that sanctifieth and they who are sanctified are all of one: for which cause he is not ashamed to call them brethren,
Saying, I will declare thy name unto my brethren, in the midst of the church will I sing praise unto thee.
And again, I will put my trust in him. And again, Behold I and the children which God hath given me.
Forasmuch then as the children are partakers of flesh and blood, he also himself likewise took part of the same; that through death he might destroy him that had the power of death, that is, the devil;
And deliver them who through fear of death were all their lifetime subject to bondage.
For verily he took not on [him the nature of: italics not in original Greek) angels; but he took on [him] the seed of Abraham.
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.
For in that he himself hath suffered being tempted, he is able to succour them that are tempted."
The author doesn’t mention Yeshua until Hebrews 2:9, and he clearly expresses that the previous verses are about a different subject. Notice right before he says "but we see Jesus", the author says "but now we see not yet all things put under him [mankind]". This is because the first two chapters are about mankind- all of mankind. Yeshua is a man, and God put all things in subjection to him because this was God's purpose from the beginning.
"Verily, verily, I say unto you, The hour is coming, and now is, when the dead shall hear the voice of the son of God: and they that hear shall live.
For as the Father hath life in himself; so hath he given to the son to have life in himself;
And hath given him authority to execute judgment also, because he is the son of man." John 5:25
Letters of Saul
I'm pretty sure Saul believed that Yeshua preexisted as a divine entity, along the lines of Arianism. We could argue for thousands of years about what Saul was talking about, but there really is no need. He might have written 13 letters, but he is only one man. My answer to Why are the three accounts of Paul's conversion on the road to Damascus different? should explain why I feel no need to quote him.
Yeshua is a man because the Greek Scriptures say he is a man. When Yeshua exalts himself, he is actually exalting God and God’s word, because he says:
Jesus cried and said, He that believeth on me, believeth not on me, but on him that sent me.
And he that seeth me seeth him that sent me. [because he is the image of God]
I am come a light into the world, that whosoever believeth on me should not abide in darkness.
And if any man hear my words, and believe not, I judge him not: for I came not to judge the world, but to save the world.
He that rejecteth me, and receiveth not my words, hath one that judgeth him: the word that I have spoken, the same shall judge him in the last day.
For I have not spoken of myself; but the Father which sent me, he gave me a commandment, what I should say, and what I should speak.
And I know that his commandment is life everlasting: whatsoever I speak therefore, even as the Father said unto me, so I speak.