Isaiah 53 is a prophecy concerning Jesus (you should read the entire chapter) and I would like to focus on Isaiah 53:6-7 “All we like sheep have gone astray; We have turned, everyone, to his own way; And the LORD has laid on Him the iniquity of us all. He was oppressed and He was afflicted, Yet He opened not His mouth; He was led as a lamb to the slaughter, And as a sheep before its shearers is silent, So He opened not His mouth.” Jesus became that lamb. John the Baptist sees Jesus as the lamb but not just any lamb “the next day he saw Jesus coming toward him, and said, “Behold, the Lamb of God, who takes away the sin of the world!” John 1:29
John 1:29 begins our study in what the purpose of the cross was and what was included in the sacrifice of the Lamb of God as He was laid on the altar of the cross. First notice that John the Baptist did not say here comes Jesus, the Messiah or even the Son of God, he specifically calls Jesus the “Lamb of God”. Why? Leviticus 14:12 answers that question “The priest will take one of the male lambs and the olive oil and present them as a guilt offering, lifting them up as a special offering before the Lord.” Just as Isaiah 53 foretold that “God laid on Him the iniquity of us all” John the Baptist is also foretelling what is going to happen to Jesus, who is the Lamb of God.
Therefore one purpose of the cross was to end the sacrificial system as Jesus became the final sacrifice, Hebrews 10:1-18 and Romans 8:25.
Jesus in Luke 22:20 (NKJV) gave us another purpose for the cross “Likewise He also took the cup after supper, saying, “This cup is the new covenant in My blood, which is shed for you.” Some Bibles have “New Testament” instead of “New Covenant” and this confuses people because they think that it is referring to the 2nd half of the Bible that we call the new testament. Jesus in Luke 22:20 was referring to the new covenant that God made in Jeremiah 31:31-34 and that covenant was sealed with Jesus blood on the cross and that is the covenant that is still active now. What is this “New Covenant” and what is in it?
(Taken from Crosswalk – 9 Ways the New Covenant is better than the Old by Jesse Johnson)
1. In the New Covenant, the Holy Spirit validates God’s people.
2. In the New Covenant, the Holy Spirit’s law is internal.
3. In the New Covenant we have confidence to draw near to Christ in service of his people.
4.  In the New Covenant the church’s deacons don’t serve written rules, but we serve a spiritual reality.
5. The New Covenant gives spiritual life.
6. The New Covenant reveals God in a more glorious way.
7. The New Covenant gives righteousness.
8. The New Covenant unveils the heart.
9. The New Covenant sanctifies.
Therefore contrary to most denominational teachings not “everything” in the Old Testament was nailed on the cross and ended when Jesus died. According to the New Covenant the law of Mosses was now in or engraved on our hearts and therefore could not just end.
(The following is from http://biblicaltruth.net/) “Jesus said in Matthew 5:17 “Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfill (teach fully, bring full meaning to, or to magnify).” The word “fulfill” in the Greek is derived from (plēroō). Most believe that this means to “complete”. This word means to teach fully, bring full meaning to, or to magnify, in others words The Messiah is saying that HE came to teach the LAW to everybody in FULL, TO FULLY TEACH or TO MAGNIFY ITS MEANING. HE was showing us that what the Pharisees were teaching went against Torah. They were adding their own man-made tradition into the teaching of the Torah. The Messiah came to teach what HE meant from the beginning (TORAH). This is still alive today.”
Jesus taught the law and even raised the bar, “  I tell you the truth, until heaven and earth disappear, not even the smallest detail of God’s law will disappear until its purpose is achieved. 19 So if you ignore the least commandment and teach others to do the same, you will be called the least in the Kingdom of Heaven. But anyone who obeys God’s laws and teaches them will be called great in the Kingdom of Heaven.” Matthew 5:18-19 (Read the entire chapter 5)  why would He teach the law if He was going to end it on the cross? Jesus went after the religious leaders who have added hundreds of rules and regulations on top of the commandments and laws of God which made them unbearable and impossible to keep, Paul went after them too and you can see that in his letters. The question that needs to be asked is where in the Bible does it say that doing the 7 Biblical feasts ever ended? Where in the Bible has the Ten commandments ended? Where in the Bible has the 7th day stopped from being the Sabbath?
Romans 14 teaches that it is a matter of the heart, if one decides to worship God on Saturday and another on Sunday do not judge or look down on each other because as long as it is being down sincerely from the heart and not out of legalism it is ok them. I will caution however that just because you can do something does not mean that you should or that it is wise, Paul said “Everything is permitted,” you say? Maybe, but not everything is helpful. “Everything is permitted?” Maybe, but not everything is edifying.” 1 Corinthians 10:23  (CJB), even if you do it from the heart you can still be sincerely wrong. Therefore DO NOT JUDGE! You are not the Holy Spirit.
God himself gave another purpose for the cross when He tore the curtain in two that separated the people from the Ark of the covenant in  Matthew 27:51 (AMP) “And [at once] the veil [of the Holy of Holies] of the temple was torn in two from top to bottom; the earth shook and the rocks were split apart.” Because of the sacrifice of Yeshua (Jesus) being the perfect Lamb of God there is now direct access to God the Father.
Let us now praise our Lord and King Yeshua for His final sacrifice on the altar of the cross and worship Him when He resurrected and now is in Heaven who is going to return very soon to bring