One of the arguments biblical Unitarians use is the law of agency in order to account for the texts that portray Jehoshua as having the authority of Jehovah and apply Jehovah texts to him. I believe this is a mistake by Unitarians in order to overcompensate for the exaltation in the new testament regarding Jehoshua. Many Unitarians cite Jewish law and the Talmud for this law of agency doctrine and then read into scripture. Again, this is a poor explanation for the texts that obviously exalt Jehoshua to a high position and even apply old testament Jehovah texts to him.
Luke 3:38
"the [son] of Enos, the [son] of Seth, the [son] of Adam, the [son] of God"
Adam was the Son of God. Adam being the Son of God was not only because he was Jehovah's first creation of the Adamic-Israelite bloodline, but also because God gave him headship over His (Jehovah's) garden.
1 Corinthians 15:45
"So also it is written, The first man Adam became a living soul. The last Adam [became] a life-giving spirit"
Jehoshua is called the last Adam, showing that he is the Son of God of the new creation whereas Adam was Jehovah's Son of the old creation. Adam was given headship/kingship over the garden of Jehovah in Eden, whereas Jehoshua had headship/Kingship over the garden of Jehovah in New Jerusalem.
1 Corinthians 15:22
"For as in Adam all die, so also in Messiah shall all be made alive"
Unlike Jehoshua, Adam failed at the task Jehovah gave him. Adam's sin brought death to mankind and so all those that remain in him will die not only this death, but the second death in the lake of fire. This is why we must be in covenant with Jehoshua, the new Adam, so that we can escape the second death and be resurrected to eternal life.
Jehovah set up Adam as his first King on the earth, however Adam fell into sin and forfeited eternal Kingship. Nonetheless, Jehovah promised Adam and Eve a seed:
Genesis 3:15
"and I will put enmity between thee and the woman, and between thy seed and her seed: he shall bruise thy head, and thou shalt bruise his heel"
Jehovah told the serpent that He would raise up a seed from Adam and Eve to crush his (Satan's) head. This would be someone who would finish the task Adam couldn't.
This theme of Sonship and inheritance related to it is all over the old testament. We see this with Isaac, Jacob-Israel, Jacob's 12 sons and ultimately King David and his royal offspring.
There are clear passages in the new testament where Jehoshua is called god and even some prophecies where he is either referred to as god or Jehovah. For those who reject the Trinity and any "Jesus is God" doctrine, you will need to wrestle with this. Many biblical Unitarians utilize the so-called Jewish law of agency to explain these instances away. This, however, denigrates the Messiah into some legal agent of the Father rather than highlighting His only begotten Sonship. While biblical Unitarians do believe Jesus is God's begotten Son by way of the virgin birth, they also stay away from emphasizing that he is Jehovah's only begotten.
While there is truth in the law of agency principle it doesn't come close fo describing the reason that Jehoshua has the authority that he does nor the reason he is called god or has Jehovah texts from the old testament applied to him.
Quite frankly, the law of agency isn't impressive at all as this office can be filled by many people. For example, a process server is an agent of the lw firm that procures his services. Another example is companies who have a specific person at their company to accept service of process on behalf of the company. Some companies even have other companies be their agent to accept service of process. The law of agency principle denotes a very bland business relationship between the sender and the one being sent. No intimate relationship is required, just a legal agreement for the law of agency.
John 10;30
"I and the Father are one"
Many use this verse to say that Jehoshua and God are one person or being but that's not the point of the Messiah's statement above.
John 10:35-38
35 If he called them gods, unto whom the word of God came (and the scripture cannot be broken) ,36 say ye of him, whom the Father sanctified and sent into the world, Thou blasphemest; because I said, I am [the] Son of God? 37 If I do not the works of my Father, believe me not. 38 But if I do them, though ye believe not me, believe the works: that ye may know and understand that the Father is in me, and I in the Father.
Jehoshua clarifies exactly who he is in his response to the Judean leadership and that identity is him being the Son of God. He also says that the Father is in Him and he is in the Father, which denotes intimate covenant relationship. This far surpasses any type of agency concept.
John 5:18
"For this cause therefore the Judeans sought the more to kill him, because he not only brake the sabbath, but also called God his own Father, making himself equal with God"
This is a statement made by John the apostle regarding the Judean leadership persecuting Jehoshua for healing an infirm man on the Sabbath day. Jehoshua's response to the Judean leadership was that both him and his Father (Jehovah) work on the Sabbath. Obviously, this is not just any work but it's Kingdom work. However, the point made by John the apostle is that indeed Jehoshua broke the Sabbath and even made himself eqaul with Jehovah by calling Him Father.
Most Christians think that this is just the Judean leadership falsely accusing Jehoshua, but we have to remember that these are the words of the apostle John not the Judean leadership. They think to themselves, "what in the world would give the right for Jehoshua to break the Sabbath?". John's very next statement is the answer to this, which is that Jehoshua called Jehovah His own Father making him eqaul with the Father. Although most Christians don't have a problem with this part of the verse due to their Christology, it's likely that either both statements have to be true or they both have to be false accusations. So, in effect most Christians disagree with the first part but accept the second part. Most Unitarians reject both parts of the verse as true.
Both of these statements by John the apostle are connected, in that the very reason Jehoshua could break the Sabbath was because God was His Father and he possesses an eqaulity with God due to that Sonship. Jehoshua being the literal begotten Son of Jehovah is what gives him the authority to break the old covenant Sabbath. To be the Son of God was to be the King of Israel and the King had authority to be a law giver (Genesis 49:8-10). From the time of his baptism, Jehoshua was no longer under the law of Moses since the law was until John the Baptist.
From the time of John the Baptist onwards, the gospel of the Kingdom was being preached and men were pressing into it. This Kingdom's King was Jehoshua and it was a new Kingdom, therefore a new law was needed. The new law was given from the sermon on the mount and there was nothing about the seventh day sabbath keeping as part of that law. Instead, Jehoshua was bringing a new understanding of Sabbath keeping that went beyond keeping one day holy. Doing good works and resting in the grace of Jehovah God everyday became the new covenant Sabbath (Hebrews 4).
As stated above, Jehoshua had the right to break the old covenant Sabbath because He was Jehovah's Son and not a servant to the Mosaic system of worship:
Hebrews 3:5-6
5 And Moses indeed was faithful in all his house as a servant, for a testimony of those things which were afterward to be spoken; 6 but Messiah as a son, over his house; whose house are we, if we hold fast our boldness and the glorying of our hope firm unto the end.
This right here explains exactly why Jehoshua had the right to break the Sabbath, which is that he is the only begotten Son of God and is over the new covenant house of God (the church). Moses was only a servant in the old covenant house of Jehovah (the Tabernacle). This shows that Jehoshua, although born under it, was not under the law of Moses once he was anointed as King of Israel in the Jordan river.
John in verse 18 of John chapter 5 connects the two things we are discussing here, one that Jehoshua did break the Sabbath, and two, that Jehoshua is eqaul to God because is the Son of God. John gives us the answer right here in that Jehoshua's Sonship and eqaulity with the Father gave him authority to break the old covenant Mosaic Sabbath. Jehoshua's status as only begotten Son is so much more superior to Moses. Elsewhere, Jehoshua cites King David violating the Sabbath as David and his men and ate the showbread of the Tabernacle:
Mark 2:25-28
25 And he said unto them, Did ye never read what David did, when he had need, and was hungry, he, and they that were with him?26 How he entered into the house of God when Abiathar was high priest, and ate the showbread, which it is not lawful to eat save for the priests, and gave also to them that were with him?27 And he said unto them, The sabbath was made for man, and not man for the sabbath:28 so that the Son of man is lord even of the sabbath.
According to Jehoshua, King David broke the Sabbath and it was incident that Jehoshua cited as the right for him and his disciples to pluck the ears of the grain. Why does Jehoshua cite David as justification for him breaking the Sabbath? Because like David, Jehoshua is Jehovah's begotten Son and anointed King (Messiah). It was David's Sonship and Kingship that gave him this right not some bland plastic law of agency. Jehoshua's statement in verses 27 and 28 is powerful as he gives the true intent of the Sabbath rest as well as stating that he is Lord (King) of the Sabbath.
If King David had a right to break the Sabbath and the law by eating the shewbread of the Tabernacle, then why should we have an issue with Jehoshua breaking it. Remember, King David was under the law but his Sonship and Kingship gave him authority to break it in this instance. Also, Jehoshua ia greater than David and is Jehovah's only begotten Son therefore there should be no issue in agreeing with John's statement in John 5:18 that he broke the Sabbath.
The overall point is that Jehoshua's Sonship gives him an eqaulity with the Father and therefore, he has authority to break the Mosaic covenant Sabbath because as the Son of God he is not under the Mosaic law. Remember, the law was until John the Baptist showing that once Jehoshua got baptized he was no longer under that law. Instead of being required to keep the law of Moses, Jehoshua was sent to give us a new law befitting the new covenant. As the Judean King he was to be a law giver (Genesis 49:8-10), however since he was ushering in a new covenant, a new law was required as it would be under a different priesthood:
Hebrews 7:11-12
11 Now if there was perfection through the Levitical priesthood (for under it hath the people received the law), what further need [was there] that another priest should arise after the order of Melchizedek, and not be reckoned after the order of Aaron? 12 For the priesthood being changed, there is made of necessity a change also of the law.
Jehoshua was anointed as both King and High Priest at the Jordan river and therefore was not under the law since that time being that he is a priest after the order of Melchizedek. This proves then that Jehoshua was not under the Sabbath law and was instead Lord of it.
John 5:19-23
19 Jehoshua therefore answered and said unto them, Verily, verily, I say unto you, The Son can do nothing of himself, but what he seeth the Father doing: for what things soever he doeth, these the Son also doeth in like manner.20 For the Father loveth the Son, and showeth him all things that himself doeth: and greater works than these will he show him, that ye may marvel.21 For as the Father raiseth the dead and giveth them life, even so the Son also giveth life to whom he will.22 For neither doth the Father judge any man, but he hath given all judgment unto the Son;23 that all may honor the Son, even as they honor the Father. He that honoreth not the Son honoreth not the Father that sent him.
Jehoshua being equal with Jehovah God does not mean that he doesn't totally rely on Jehovah God, but rather it highlights the privileges bestowed up the Son of Jehovah. Jehoshua have eqaulity with the Father has nothing to do with them being of the same substance, but rather its because the Father loves the Son. Because of the intimate relationship between Jehovah and Jehoshua, the Father (Jehovah) shows the Son (Jehoshua) all the things that He Himself does. This shows that like any earthly son and father relationship, Jehoshua learns everything from His Father Jehovah and does great works, shown to him by the Father, that we may marvel.
Just as Father raises the dead, the Son has been given the power to raise the dead from the Father. This was done in Jehoshua's Kingdom mission and will again be done at the last day. Even now, Jehoshua raises those who are spiritually dead unto newness of life. Jehoshua's eqaulity with the Father is rooted in their intimate Father-Son relationship and it's this intimate relationship that is the reason the Father has given all judgment to the Son. The law of agency doctrine doesn't even begin to do justice to the relationship and eqaulity Jehoshua has with the Father. And why does the Father show the Son all things and give him all judgement? So that all may honor the Son as they honor the Father!
This doesn't mean that the Son is Jehovah God or part of a triune Godhead and that we need to honor him as such. This statement by John has nothing to do with substance. This statement by John the apostle simply means that we must honor Jehoshua as Jehovah God's only begotten Son and that because of his Sonship we are to understand that he has an eqaulity with his Father. The law of agency would say that this eqaulity is a functional one, whereas the Jehoshua is God people would say this eqaulity is based on substance. Neither of these is the truth as Jehoshua's eqaulity with Jehovah God is rooted in intimate relationship. Those who fail to honor Jehoshua as Jehovah's precious only begotten Son disrespect Jehovah God Himself.