The lack of the Oral Torah in Christianity actually causes more problems for Christianity than it helps. It seems to me that there are two possibilities for why Christianity dropped the Oral Torah from their belief system. The first possibility is that, the Roman Emperor Constantine, in his epistle mandate to the bishops not assembled for the Council of Nicea in 325 CE gave them the mandate that they should sever all ties with Judaism for good. This means that he wanted Christianity to be completely free from Jewish influence, including any observance of the Torah, both the Written Torah and the Oral Torah. It is a well attested fact that Constantine wrote this letter, and even though the letter has survived until the present, it's not really talked about much in Christian circles. You can easily find the letter online through a Google search, and at least one Messianic website (Kad-Esh MAP Ministries, click here to read the article) also has the letter posted in an article on their website. I suspect that the reason it's not talked about much is because it's absolute proof that the Christian religion was manufactured at the Council of Nicea, and the fact that the religion was man-made based on a vote is not really the sort of thing that anyone wants to know about their belief system. While it is well known among the scholarly elite in the Christian world that this is the truth, the role of the Council of Nicea in creating Christianity as we know it today is downplayed for the sake of not destroying the faith of the billions of Christians in the world. And while I disagree with the decision to not speak out about the real origins of Christianity on the part of these Christian scholars, I understand it and don't blame them for not letting the truth be known. However, there is a small minority of Christian scholars who are very vocal about Christianity's origins, but you probably will never see them speak in a church because most of them are branded as heretics for not accepting the authorised Christian version of history. The second possibility for why Christianity doesn't utilise the Oral Torah is less nefarious by far, the bishops at the Council of Nicea never learned the Oral Torah because they weren't taught by people who learned it from the disciples of Yeshua/Jesus, so they couldn't teach what they didn't know.
Whatever the reason that modern Christians aren't taught the Oral Torah may be, a lack of the Oral Torah has disastrous effects on the theology of the Christian religion, and even worse effects on the Messianic movement within Christianity which claims to be a legitimate form of Judaism. The first problem, and probably the biggest one, that the lack of the Oral Torah in Christianity causes is that the Messiah-ship of Yeshua/Jesus is completely undone. As was stated in the article about the requirements of the Messiah, one of the requirements for the Messiah is that he has to be Jewish and from the right genealogy. The gospels make it clear that Yeshua/Jesus didn't have a human father, and while I don't believe that for a second, it's not important right now because a person is born Jewish only if the person's mother was Jewish. As noted in the article about the requirements of the Messiah, Jewish identity is passed exclusively through the mother. This is clearly taught in Scripture. A minor issue in the big problem of the Jewishness of Yeshua/Jesus is that the gospels give two distinct and contradictory genealogies of Yeshua/Jesus, and both of them purport to be the genealogy of Joseph, the "father" of Yeshua/Jesus. This means that the gospels don't give us a genealogy for Yeshua/Jesus at all since they mention the genealogies of a man who isn't his father (according to the gospels themselves), and they don't mention his mother's genealogy. If they mentioned that his mother was Jewish, we could say for certain that Yeshua/Jesus is Jewish, but we can't say for certain if he is a Jew at all. Let's assume that he is though, just to show exactly why Christianity needs the Oral Torah. So we assume that he was born a Jew, we still have the problem that the Messiah must be a patrilineal descendant of King David through his son King Solomon, as noted in the article about the requirements for Messiah. So let's assume that Yeshua/Jesus was really the physical son of Joseph and that Joseph had the correct genealogy, for argument's sake. This would make Yeshua/Jesus a valid candidate for Messiah in his lifetime. Now we have a new issue in Yeshua/Jesus' genealogy, he's not of 100% native born Jewish descent because King David wasn't. King David's great-grandmother was a woman named Ruth, the same Ruth that the book of Ruth is written about. But Ruth was born a Moabite, which is a problem because the Written Torah says that a Jew is forbidden from marrying an Ammonite or Moabite and Ammonites and Moabites are eternally banned from entering the Jewish nation (Deuteronomy 23:4, verse 3 in Christian Bibles). This is actually a problem that at least some Christian pastors are aware of because two pastors have actually asked me how Ruth was able to marry a Jew and have her children be Jewish and acceptable enough to G-d for Ruth's great-grandson to be the king of the Jewish people and the progenitor of the Messiah. While Christians are generally good at reading their Bibles, they rarely seem to catch the full meaning of what they read. I say this because if a Christian had read Deuteronomy 23:4 (verse 3 for Christians), and they read the book of Ruth, logic would demand that King David was not Jewish and was illegitimate as a king and as a Jewish child. In the absence of the Oral Torah, and using only the Written Torah, Yeshua/Jesus could never be the Messiah because he's descended from a Moabite woman. This is especially problematic because not only is King David the great-grandson of a Moabite, but King Rehoboam, King David's grandson (King Solomon's son), is the son of an Ammonite mother, both Ammonites and Moabites are eternally banned from entering into the Jewish people. So a plain reading of the Written Torah delegitimises the Davidic monarchy, meaning that Yeshua/Jesus could absolutely have never been the Messiah. So without the Oral Torah, Christians don't have a Messiah. But the Oral Torah tells us in the Talmud Bavli (tractate Yevamot 77b) that the restriction against a Moabite or Ammonite marrying into the Jewish people applies only to males and not to females. Since the prohibition of a Moabite or Ammonite entering into the Jewish people only applies to males, Christianity would have less problems if it just taught the Oral Torah. According to the Oral Torah, a female Moabite or Ammonite can marry into the Jewish people, which makes King David and King Rehoboam both fully Jewish and acceptable as kings and the progenitors of the Messiah. According to the gospel of Matthew (but not Luke), Joseph is a descendant of King David and King Rehoboam, which would make him from the Messianic line if he weren't also descended from the cursed line of King Jeconiah (Jeremiah 22:30). But the point is that the biggest problem for the Messiah-ship of Yeshua/Jesus can be erased if Joseph were the physical father of Yeshua/Jesus and Christians got a bit of help from the Oral Torah. In defence of Christianity, I've never heard their argument for why Yeshua/Jesus could be the Messiah without the Oral Torah, so I just don't know how good their argument is, but I'm fairly certain that they have an argument of some sort.
Another problem for Christianity that could be alleviated if they accepted the Oral Torah is the problem of the actual teachings of Yeshua/Jesus. Many of the teachings of Yeshua/Jesus are found in the Oral Torah. For example, the "Golden Rule" of "do unto others as you would have them do unto you" (Matthew 7:12) is actually based on the teaching of Hillel the Elder (lived 110 BCE-10 CE). Hillel is recorded in the Talmud Bavli (tractate Shabbat 31a) as saying "whatever is distasteful to you, don't do this to your fellow. This is the whole Torah, the rest is commentary, go and learn". This teaching didn't originate with Yeshua/Jesus, it came before his birth, he just added to it in a way that is a bit questionable in the respect that you never know if someone wants to be treated like you want to be treated, but you can be assured that someone most likely won't want to be treated in a way that you would consider distasteful. The teaching of Yeshua/Jesus about obeying the Pharisees' instruction (Matthew 23:3) makes no sense without the context that Jewish history provides. The Pharisees were the largest of just a couple of sects who taught the Oral Torah. If the Oral Torah were a rabbinical invention, Yeshua/Jesus wouldn't have taught his disciples to follow the teachings of the Pharisees. Additionally, the majority of Yeshua/Jesus' teachings come directly from either Scripture or the Oral Torah. In fact, in one dispute that Yeshua/Jesus had with the Pharisees (Luke 6:1-4), he uses a method of interpreting Scripture found exclusively in the Oral Torah to defend his disciples, though he does get all the details of the Scriptural story he quotes wrong. If Christianity taught the Oral Torah, it would solve the mystery behind most of Yeshua/Jesus' teachings. The irony is that not only can the Written Torah and the rest of the Tanach (Jewish Scripture) only be understood properly with the Oral Torah, but you can't even understand the actual teaching of Yeshua/Jesus in the gospels without the Oral Torah. It seems to me that most Christians would argue that Yeshua/Jesus condemned most of the Oral Torah teachings of the Pharisees, but only endorsed the ones he used, to which I would simply respond that this is too easy to say with no evidence to back it up, and it's a stretch to say since Yeshua/Jesus never specifically spoke against the Oral Torah. In fact, he never listed his source for his teachings, so we can safely assume that he viewed the Oral Torah as a valid and authoritative teaching from G-d.
The Oral Torah also clears up minor issues in the New Testament like the washing hands before eating a meal that's mentioned in the gospel of Mark 7:2, and the issue of why the Jewish leadership wouldn't enter a Roman house before the festival of the Pesach (Passover) that's found in the gospel of John 18:28.
The Oral Torah can clear up most of the major and minor issues found in the New Testament, but not all of the issues in the New Testament. For example, Yeshua/Jesus directly contradicts the Oral Torah when he famously remarks that "not one stone will remain on top of another" in reference to the Temple in Matthew 24:2. History has proven Yeshua/Jesus dead wrong about this matter since the Western Wall (the Kotel) is still standing firm, but that doesn't seem to be a problem for the Christian world for some reason. According to Shir HaShirim Rabbah, chapters 2-8, the Western Wall would remain standing eternally. Eicha Rabbah 1:32 mentions that Rome couldn't destroy the wall because of a Divine edict that it should never be toppled. Shemot Rabbah 2:2 quotes Rav Acha in saying that the Divine Prescience has never left the wall. And the Zohar states in Mishpatim 116 that "the Divine Prescience rests in the Western Wall". If Yeshua/Jesus had been a Jewish rabbi (or G-d, as Christianity teaches), he would have known all of these, and he never would have said that not one stone of the Temple would have been left on top of another. To make matters even more embarrassing for Yeshua/Jesus, the gospel of Matthew was written after the Temple was destroyed. All the author of Matthew had to do to verify the prediction he has Yeshua/Jesus make was visit Jerusalem, so it's safe to say that the author of Matthew probably only heard of Jerusalem and never visited.
As much as it may seem like the New Testament comes out in favour of the Oral Torah because of how much could be cleared up easily with the wealth of knowledge contained within the Oral Torah, the New Testament is not very favourable to the Oral Torah, and Christianity in general is hostile to the Oral Torah. For example, in the passage in Matthew 23 that I mentioned earlier where Yeshua/Jesus specifically tells his disciples to follow whatever the Pharisees say, immediately afterward Yeshua/Jesus goes on to berate and make up outright slanderous lies about the Pharisees. The take away from that is that the Christian should love the teachings of the Pharisees, but at the same time not have anything else to do with them because of how evil they really are, and a plain reading of the text will give anyone that impression. That's not so much a statement against the Oral Torah as much as it is an attack against the only surviving ones who teach and keep the Torah and against their credentials. In 1 Timothy 1:3-4, the author (believed to be the apostle Paul) directs his audience (believed to be Paul's disciple Timothy) with these words: "As I besought thee to abide still at Ephesus, when I went into Macedonia, that thou mightest charge some that they teach no other doctrine, neither give heed to fables and endless genealogies, which minister questions, rather than godly edifying which is in faith (KJV)." I want to take just a moment to acknowledge the irony that "endless genealogies" are employed in the gospels of Matthew and Luke to attempt to demonstrate that Yeshua/Jesus is a valid candidate for Messiah, but here we can see the New Testament saying not to let people pay attention to "endless genealogies". In another letter believed to be written by the apostle Paul, the author says this: "Wherefore rebuke them sharply, that they may be sound in the faith; not giving heed to Jewish fables, and commandments of men, that turn from the truth (KJV, Titus 1:13-14)". "Jewish fables" and "commandments of men" are the key words, and it's not hard to see that they could easily be interpreted to apply to the Oral Torah, and they have been interpreted by many Christians to be speaking against the Oral Torah. A rational person would at least listen to a Jew about the validity of the Oral Torah since we have been the only ones keeping the Torah for the past 3,300 years and we acknowledge that we can only keep the Torah because of the instructions in the Oral Torah. But as you can see, the Oral Torah isn't exactly a welcomed topic in Christianity even though it helps to explain a lot of the New Testament.
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