Why it's important to remember when Jesus said he came not to destroy but to fulfill the covenant

 17 “Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them. 18 For truly, I say to you, until heaven and earth pass away, not an iota, not a dot, will pass from the Law until all is accomplished. 19 Therefore whoever relaxes one of the least of these commandments and teaches others to do the same will be called least in the kingdom of heaven, but whoever does them and teaches them will be called great in the kingdom of heaven. 20 For I tell you, unless your righteousness exceeds that of the scribes and Pharisees, you will never enter the kingdom of heaven.

-Matthew 5:17-20

Now, most Christians are familiar with this, but this post is written to explain why so many Christians and non-Christians tend to get this wrong.

I shall address each group that tends to get this wrong in turn and explain further.

Non-believers: A very typical canard of non-believers, especially atheists looking for a cheap "gotcha", is to randomly quote one of the Old Testament laws as if they still apply, and whenever Christian try to explain Jesus fulfilled their ceremonial and ritual purpose while any moral law on their founding remains unchanged, that's when they drop one of two punchlines

1. That Christians pick and choose what they want to believe.

2. That we are not consistent.

Both are false and for the same reason. The original covenant was between God and the Israelites, who would become known in New Testament times as the Jews. Non-Israelites/Jews could enter into the covenant but had to become culturally Jewish in order to do so. When Jesus fulfilled the original covenant and began what Christians refer to as the new covenant, he simply did away with the need to become culturally Jewish.

That does not mean a Christian cannot observe the ceremonial and ritual law that applied to the Jews, insofar as possible in modern-day, that is still possible, and as Jesus said above, that's even laudable. However, the ceremonial and ritual aspect was fulfilled by Jesus becoming the perfect sacrifice, therefore, while we are not allowed to pretend the past did not happen (as Jesus put it, not an iota or dot of all that came before will be done away with), we do not have to observe the ceremonial and ritual aspects, while we are not allowed to pretend they never happened nor are we to forget their moral purpose, which is to be a holy people dedicated to the glory of God.

Jews: The Jewish community may find it strange Christians are told the "letter" of the law (the ceremonial and ritual laws that bound the Jews to God) is not strictly required, while the "spirit" (the moral aspect) still does apply. As I mentioned above, no Christian is, unless God specifies otherwise (such as when Peter was told any edible animal could be eaten, regardless of the clean and unclean laws), barred from honoring the ceremonial and ritual laws. However, Christians believe Jesus fulfilled their purpose when he became the perfect, sinless sacrifice on the cross in a way no mortal atonement could ever fulfill. Also, when Jesus died on the cross, the veil that separated the Holy of Holies, the most sacred part of the temple, from the rest of the world, was rent asunder.

When that happened, Jesus became the middleman between ourselves and God, allowing us to redeem ourselves by being a sacrifice utterly bereft of sin, thus being the only perfect thing in God's eyes capable of being seen without flaw for our redemption.

Ergo, no Christian MUST still follow the ceremony and ritual that bound the Jews, so long as we do not forget why it was done and still honor all the moral reasons behind it, as Christians, like the Jews, must set ourselves apart as holy to the Lord as the Jews had to.

Christians: In the modern-day, most Christians have no problem with all I said above, it's almost taken for granted in most denominations. However, that was not always the case.

Early on in the history of the church, some, especially in the early church, wanted to reject that Jesus was ever born in a mortal form, wanting to believe he was wholly divine in form as well as spirit, partially because they did not want to accept the past of the Old Testament, and partially because they did not understand why Jesus had to be born a mortal man with God's own spirit.

As to the first objection, Jesus himself made it clear: We MUST accept that past, no matter how ugly, controversial, or unappealing it may be. It happened. You deny that past, you deny God.

As to the second, this is why Jesus was the perfect fulfillment of the Jewish law. Under the Jewish covenant, when Man sins, one had to sacrifice an animal in the presence of the Lord to atone for sin. However, no mortal sacrifice could ever be done without it being a flawed being, as imperfect as the party who sacrificed it, so no sacrifice could ever be a permanent one to atone for our sins.

However, when Jesus died on the cross, he gave his own mortal flesh up as the sacrifice we could never make ourselves. Jesus was born a mortal, but his spirit remained utterly divine, and no blemish of evil or sin had stained him when he died. Therefore, he was the fulfillment of all the sacrifices made before, and thus that act of sacrifice proved the ultimate one for the rest of eternity for our own sin, provided we accept Jesus as our Lord and that through him is the way to the Father.

In essence, Jesus fulfilled the original covenant, and what follows since is us honoring that fulfillment so long as we remain in honor of the history, intent, and purpose of all that came before it.