What separates Mormonism from other versions of Christianity, is that Joseph Smith was obsessed with the Israelite religion. At one point he even said that in the future animal sacrifices would be restored to the temple!
Mormonism is better understood when one realizes that it is a restoration of ancient Israelite Religion: wherein Joseph Smith taught that Mormons are actual Israelites of the tribe of Ephraim or Mannasah, or they need to have their blood literally replaced with Israelite blood. This site explains:
This is currently taught in the chapter 21 of the Religion 430-431 - Doctrines of the Gospel Student Manual. The bottom of page 57 says the following:
"This first Comforter or Holy Ghost has no other effect than pure intelligence. It is more powerful in expanding the mind, enlightening the understanding, and storing the intellect with present knowledge, of a man who is of the literal seed of Abraham, than one that is a Gentile, though it may not have half as much visible effect upon the body; for as the Holy Ghost falls upon one of the literal seed of Abraham, it is calm and serene; and his whole soul and body are only exercised by the pure spirit of intelligence; while the effect of the Holy Ghost upon a Gentile, is to purge out the old blood, and make him actually of the seed of Abraham. That man that has none of the blood of Abraham (naturally) must have a new creation by the Holy Ghost. In such a case, there may be more of a powerful effect upon the body, and visible to the eye, than upon an Israelite, while the Israelite at first might be far before the Gentile in pure intelligence” (Smith, Teachings,)
[A commenter Crobbin 17 writes:]
I always thought that it was more of a symbolic thing. I can’t believe that the manual is this explicitly “you will literally be a relative of Abraham, here’s your DNA switcheroo.”
PastafarianGawd writes:
"This is actually quite endearing to my Jewish friends"
My Jewish friends' eyes can't roll back any farther in their heads when I tell them I'm "of the tribe of Ephraim," though they are impressed that I even know what that is. LOL.
Added link to Teachings of Prophet Joseph Smith. See page 149-150 [https://scriptures.byu.edu/tpjs/STPJS.pdf]:
“...while the effect of the Holy Ghost upon a Gentile, is to purge out the old blood,[3] and make him actually of the seed of Abraham.[4] That man that has none of the blood of Abraham (naturally) must have a new creation by the Holy Ghost. In such a case, there may be more of a powerful effect upon the body, and visible to the eye, than upon an Israelite, while the Israelite at first might be far before the Gentile in pure intelligence.”
Footnotes:
[3]. Isa. 4:4; Heb. 9:22.
[4]. John 8:33,37; Gal. 3:29;
D&C 84:34; D&C 103:17;
Abr. 1:4; Abr. 2:10.
Also see: Of the House of Israel By Daniel H. Ludlow.
When this is understood one can see that Joseph Smith is presenting a different spiritual concept than what the New Testament teaches.
In brief, the New Testament is basically saying that with the destruction of the Temple in 70 AD, God is choosing to graft in gentiles/pagans into Israel but not through 1st century Israelite religiosity (Torah-observance and Temple attendance, etc ). The New Testament is saying that God's spiritual presence (divine energy or substance) originally resided in a physical Temple. But now, post 70 AD, Christ as the monogene of Jehovah, is a divine-life donor deity, acting as a fluid substance (divine energy) that fills new containers (human containers): as Christians become the New Temple and Christ is the Torah written on their heart. Therefore, there is no longer the need for priests or high demand Pharasaical religion because (1) gentiles are made righteous through Christ alone and (2) there's no Temple for a priest to enter anymore! Christians themselves become the only Temple of God as a corporate body.
Because Mormonism rejects all of this and brings back the Israelite Priesthood, Temple, and Israelite lineage and bloodlines (with LDS claiming they are from the Israelite tribe of Ephraim or Manasseh), what comes with that is the restoration of high demand religion: very similar to the high demand religion of the sect of the Pharasess described in the Gospels.
As well as a restoration of the ancient Temple religion of the Sadducees and only the high priest entering the holy of holies. According to this site:
The Sadducees were elitists who wanted to maintain the priestly caste ... The focus of Sadducee life was rituals associated with the Temple.
The Sadducees disappeared around 70 A.D., after the destruction of the Second Temple. None of the writings of the Sadducees has survived, so the little we know about them comes from their Pharisaic opponents.
So besides reinventing the priestly caste elitism of the Sadducees, Mormonism also reestablishes the obsessive compulsive tradition of holiness (the Tradition of the Elders) preached by the Torah-observant Pharisees as described in the Gospels. This is why in the Mormon Church you do not have the concept of "saved by grace alone" but instead an emphasize on earning a perfect "worthiness status," in order to enter the LDS Temple and gain one's exaltation. Mormons are basically reestablishing Temple religion, quasi Torah-observance and Priests needing to be super holy to enter through the veil.
As this LDS article explains:
Anyone, regardless of religion, may enter a Latter-day Saint meetinghouse and attend services. However, because of the sacredness of temples as “houses of the Lord,” only members of the Church, who are in good standing are allowed to enter the temples. A member must be observing the basic principles of the faith and attest to that fact to his or her local leaders once every two years in order to enter a temple.
The terms "good standing" and "observing," are basically code words for the LDS Covenant Path which is very similar to ancient Israelite Temple religion and the 613 Laws of the Torah.
If you think about it, this undoes what the New Testament describes as the work of Christ, with Christ removing the barrier of the curtain in the temple and access to God's Presence.
This website explains the traditional Christian view:
During the lifetime of Jesus, the holy temple in Jerusalem was the center of Jewish religious life. The temple was the place where animal sacrifices were carried out and worship according to the Law of Moses was followed faithfully. Hebrews 9:1-9 tells us that in the temple a veil separated the Holy of Holies—the earthly dwelling place of God’s presence—from the rest of the temple where men dwelt. ... at the moment of Jesus’ death on the cross so much more momentous. “And when Jesus had cried out again in a loud voice, he gave up his spirit. At that moment the curtain of the temple was torn in two from top to bottom” (Matthew 27:50-51a, what do we make of this? What significance does this torn veil have for us today? Above all, the tearing of the veil at the moment of Jesus’ death dramatically symbolized that His sacrifice, the shedding of His own blood, was a sufficient atonement for sins. It signified that now the way into the Holy of Holies was open for all people, for all time, both Jew and Gentile. When Jesus died, the veil was torn, and God moved out of that place never again to dwell in a temple made with human hands (Acts 17:24). God was through with that temple and its religious system, and the temple and Jerusalem were left “desolate” (destroyed by the Romans) in A.D. 70, just as Jesus prophesied in Luke 13:35. As long as the temple stood, it signified the continuation of the Old Covenant. Hebrews 9:8-9 refers to the age that was passing away as the new covenant was being established (Hebrews 8:13). In a sense, the veil was symbolic of Christ Himself as the only way to the Father (John 14:6). This is indicated by the fact that the high priest had to enter the Holy of Holies through the veil. Now Christ is our superior High Priest, and as believers in His finished work, we partake of His better priesthood. We can now enter the Holy of Holies through Him. Hebrews 10:19-20 says, “We have confidence to enter the Most Holy Place by the blood of Jesus by a new and living way opened for us through the curtain, that is, his body.” Here we see the image of Jesus’ flesh being torn for us just as He was tearing the veil for us. The profound significance of the tearing of the veil is explained in glorious detail in Hebrews. The things of the temple were shadows of things to come, and they all ultimately point us to Jesus Christ. He was the veil to the Holy of Holies, and through His death the faithful now have free access to God. The veil in the temple was a constant reminder that sin renders humanity unfit for the presence of God. The fact that the sin offering was offered annually and countless other sacrifices repeated daily showed graphically that sin could not truly be atoned for or erased by mere animal sacrifices. Jesus Christ, through His death, has removed the barriers between God and man, and now we may approach Him with confidence and boldness (Hebrews 4:14-16).
At this time Gentiles were not allowed to enter certain areas of the Jerusalem Temple, see image below:
The Temple came to be seen in early Christianity as representative of lineal ethnic priesthood religion that divides Jews and Gentiles. With the temple destroyed, early Christians saw this as a symbol of God turning to the Gentiles and replacing ethnic Temple religion with the spirituality of Christ in you, i.e. God's Presence moving from a physical Tabernacle to human tabernacles; where there is no longer ethnic divisions, no Jew nor Gentile. The Gospel authors are interpreting the destruction of the temple in 70 AD as evidence of Paul's early theology of Gentile inclusion into Israel, not through Temple attendance and Torah-observance and Jewish bloodlines and priesthood but through Christ alone.