It's my position that verses (like those you've quoted above from the book of Isaiah) are in direct opposition to the words spoken by the prophet Moshe. We are told in the Torah, that anyone bringing a message contrary to that spoken by Moses shall not be listened to, for he is a false prophet.
YHWH and Moses state in the Torah that no one can "become" a Levite.
Does YHWH contradict Himself?
Or is it fact that the Law shall not pass away as long as there is Heaven and Earth?
The prophet Moses was never seen as the FINAL stop for where the Lord would develop things, as that'd be akin to saying he was greater than Abraham (or Noah prior to that) - as the Lord guiding the prophets for what was to come in the future at the Lord's command is not the same as saying God was ignoring Moses. It was the Lord who commanded and who has all ability to develop further as He sees fit - in the same way it was when seeing how things progressed from Seth to Noah to Abraham and all the way into Moses' day. The Lord never said that all forms of priests could only be found in the Levite model - nor was the Torah ever limited to that concept (as it was not just the first 5 books but also the entirety of God's work in his people) when seeing the Writings/Prophets in their actions. Thus, the real question isn't "Does YHWH contradict Himself?" but rather "Does one understand contradiction in the same manner that YHWH does or know the dynamic of Change he already made with regards to the Law?" -
This extends beyond what occurred in the OT....specifically
when realizing that others greater than Moses would arise and
Yeshua paralleled the life of Moses in many respects. For we understand that the purpose of Yeshua's life and work was to fulfill both the Law (the books of Moses) and the Prophets (other Old Testament books) - and He did not destroy the Old Testament. However, when the Lord said “I have not come to abolish the Law or the Prophets,” it's logically consistent with the culture of the OT that he did not mean that each specific law would stay exactly the same. Rather, he meant that the purpose and message of the Law and the Prophets remain exactly the same. ..for the Law and the Prophets pointed to him and were intended from the beginning to be fulfilled by him in every dynamic necessary. At the end of the day, it is Yeshua as the Son of God who has more authority than Moses had (Hebrews 3:1-6) - and Yeshua is the standard by which Moses is judged. Whereas Moses wrote many chapters about the tabernacle and the “place” in which God put his name, we see where Yeshua noted that place did not matter (John 4:20-24).
And we understand where Moses even prophesied that the Messiah would come - one with authority as He had it - as seen in Deuteronomy 18:15: "
The Lord your God will raise up for you a prophet like me from among your own brothers. You must listen to him." And we can also see the same promise in the Lord's Own words from Deuteronomy 18:18:
"I will raise up for them a prophet like you from among their brothers; I will put my words in his mouth, and he will tell them everything I command him.". This was fulfilled in the person of Yeshua. For when he performed the miracle of feeding the 5000 in John 6, the crowd said
"Surely this the Prophet who is to come into the world" (John 6:14). Additionally, when he spoke to the multitiudes at the Feast of Tabernacles, some of the people exclaimed,
"Surely this man is the Prophet" (John 7:40).. Moreover, when the Jews questioned the legitimacy of Christ, the Lord noted directly that they really did not understand Moses' words (as they continually accused him of breaking the Law or Sabbath - not knowing the difference between fulfilling something and "breaking" as they saw it), as seen when he said
" 45 Do not think that I shall accuse you to the Father; there is one who accuses you—Moses, in whom you trust. 46 For if you believed Moses, you would believe Me; for he wrote about Me. 47 But if you do not believe his writings, how will you believe My words?”" (John 5:46).
As it concerns what the Prophet Isaiah noted in
Isaiah 66:21
Isaiah 66:21
And some of them also I will take for priests and for Levites, says the LORD.
, Isaiah was not a false prophet for what he noted when it came to saying others would be made into Levites BY THe Lord's command. That would be akin to saying the Master of the house has no right to change his policy as he sees fit - and that's not what the Lord ever indicated he supported. Policy changing is not the same as policy passing away - it will always be in the memory of events on what occurred...and recorded for reference in showing how things built up. Nonetheless, the fact that it occurred isn't the same as saying that all practices would be exactly as it in the future - nor does it mean that differing practices are the same as saying that the Law is gone. The Lord would be perfectly within his rights to ensure that certain Gentiles be made into priests for spiritual worship, enjoying the direct access to God which was formerly enjoyed by the ministers of the temple alone ( 1 Peter 2:9 , Revelation 1:6 ).