Jesus fulfilled the law by His life and abolished the law by His death on the cross.

The message of the Cross was a mystery that was hidden by God until Jesus died.

1 Corinthians 1-2 “we preach Christ crucified: a stumbling block to Jews and foolishness to Gentiles, 24 but to those whom God has called, both Jews and Greeks, Christ the power of God and the wisdom of God…..a mystery that has been hidden and that God destined for our glory before time began. 8 None of the rulers of this age understood it, for if they had, they would not have crucified the Lord of glory.”

The world was under the Law until Jesus died on the cross.
So when Jesus came, He did not want the Jews to know that He was the Messiah who was going to die on the cross (Luke 9:21, Matt 16:20).
If they knew that then they would not crucify Him.

He did not preach the Grace Gospel of His death and Resurrection.
Instead He preached the law before the cross because He came to obey the law first before His crucifixion.

Matthew 5 “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.”

Jesus came as God in the flesh, the first man and only man to obey the Law perfectly.

Under the Law, man could receive eternal life only by obeying the works of the law/commandments.

Leviticus 18 ” 5 Keep my decrees and laws, for the person who obeys them will live by them”

Matthew 19 “16 Just then a man came up to Jesus and asked, “Teacher, what good thing must I do to get eternal life?” 17 “Why do you ask me about what is good?” Jesus replied. “There is only One who is good. If you want to enter life, keep the commandments.” 18 “Which ones?” he inquired. Jesus replied, “‘You shall not murder, you shall not commit adultery, you shall not steal, you shall not give false testimony, 19 honor your father and mother,’ and ‘love your neighbor as yourself.’” 20 “All these I have kept,” the young man said. “What do I still lack?” 21 Jesus answered, “If you want to be perfect, go, sell your possessions and give to the poor, and you will have treasure in heaven. Then come, follow me…..25When the disciples heard this, they were greatly astonished and asked, “Who then can be saved?” 26 Jesus looked at them and said, “With man this is impossible, but with God all things are possible.”

Nobody could obey the law to be righteous because all men have sinned and died just like Adam.

So then Jesus came to obey the law and by His obedience, He attained eternal life. Only Jesus did it.

Hebrews 5 “7 During the days of Jesus’ life on earth, he offered up prayers and petitions with fervent cries and tears to the one who could save him from death, and he was heard because of his reverent submission. 8 Son though he was, he learned obedience from what he suffered 9 and, once made perfect, he became the source of eternal salvation for all who believe him”

Romans 5 “12 Therefore, just as sin entered the world through one man, and death through sin, and in this way death came to all people, because all sinned…..19 For just as through the disobedience of the one man the many were made sinners, so also through the obedience of the one man the many will be made righteous.”

Jesus obeyed the law in His life to attain immortality.
Jesus abolished the law by His death to give immortality to all who believe because He rose from the dead.

Romans 10 ” 4 Christ is the culmination of the law so that there may be righteousness for everyone who believes.5 Moses writes this about the righteousness that is by the law: “The person who does these things will live by them.” 6 But the righteousness that is by faith says….. 9 If you declare with your mouth, “Jesus is Lord,” and believe in your heart that God raised him from the dead, you will be saved. 10 For it is with your heart that you believe and are justified, and it is with your mouth that you profess your faith and are saved.”

But before Jesus died on the cross, He did not tell publicly tell the people about the cross or the salvation by grace.
He preached the law because He was fulfilling the law by His life.
He was preaching what He was practising.

This is why Jesus commanded people to sell everything to the poor and carry the cross (Luke 12, Luke 14) because He alone did it.

This is why Jesus commanded people to not sin and be perfect like God (Matthew 5-7) because He alone did it.

This is why Jesus commanded the people to obey the law to be saved (Matthew 19) because He alone did it.

He alone obeyed the law.
None of the Apostles did it….they all failed.
The purpose of the law was not to save us but to show people that they cannot do it.

Romans 3 “19 Now we know that whatever the law says, it says to those who are under the law, so that every mouth may be silenced and the whole world held accountable to God. 20 Therefore no one will be declared righteous in God’s sight by the works of the law”

The purpose of the law was for Jesus to obey it and save us by His obedience through the cross.

The law ended on the cross so that we are saved by grace through faith and not our works.

Ephesians 2 ” 15 by setting aside in his flesh the law with its commands and regulations through the CROSS……As for you, you were dead in your transgressions and sins……4 But because of his great love for us, God, who is rich in mercy, 5 made us alive with Christ even when we were dead in transgressions—it is by grace you have been saved. 6 And God raised us up with Christ and seated us with him in the heavenly realms in Christ Jesus, 7 in order that in the coming ages he might show the incomparable riches of his grace, expressed in his kindness to us in Christ Jesus. 8 For it is by grace you have been saved, through faith—and this is not from yourselves, it is the gift of God— 9 not by works, so that no one can boast.“

You see this is why Jesus preached so much works before the cross because the law was still in effect until He died.

After Jesus fulfilled the law in His life,
He abolished it by His death on the cross.

The Law ended and Grace began on the CROSS.

Now, we are Righteous by faith in Jesus without any works!

Romans 3 “21 But now apart from the law the righteousness of God has been made known, to which the Law and the Prophets testify. 22 This righteousness is given through faith in Jesus Christ to all who believe. There is no difference between Jew and Gentile, 23 for all have sinned and fall short of the glory of God, 24 and all are justified freely by his grace through the redemption that came by Christ Jesus. 25 God presented Christ as a sacrifice of atonement, through the shedding of his blood—to be received by faith”

This is the Good News:
Everyone who believes in Jesus Christ is forgiven all sin, made righteous without works, by grace we are saved.