Why Replace Moses’ Law with Jesus’ Sermon on the Mount?
Sermon Summary: Why Replace Moses’ Law with Jesus’ Sermon on the Mount?
Bro. Micah See | 23 November 2025 | Acts 13 : 37 – 39
In Acts 13, the apostle Paul stood before the Jews and declared that Jesus had come to bring a more perfect covenant. He emphasised
Acts 13:37–39, especially verse 39:
“and by Him everyone who believes is justified from all things from which you could not be justified by the law of Moses.”
Paul was speaking to Jews who still clung tightly to the Law even after the death and resurrection of Christ, still waiting for a Messiah who had already come. Paul had to repeatedly bring this up because they would not let go of Moses’ Law. This passage lays the foundation for why Jesus replaced Moses’ Law with the Sermon on the Mount — not to abolish truth, but to restore its essence in Himself.
1. The Decay of Moses’ Law
Paul reminded Israel of their history (Acts 13:16–22): how God chose their fathers and gave them a Law meant to be followed — yet He also gave them judges, prophets, and kings because they kept failing to keep it. God tolerated them in the wilderness for 40 years, then gave them judges, then Samuel the prophet, and after that kings. Even then, some kings were righteous, most were not. This history shows the increasing difficulty and inability of Israel to keep Moses’ Law.
The requirements of the Law had become practically impossible to carry out, especially after the destruction of Solomon’s temple and the dispersion of the Jews. Key passages show the difficulty:
Deuteronomy 12:13–14 –
“Take heed to yourself that you do not offer your burnt offerings in every place that you see: but in the place which the Lord chooses… there you shall offer your burnt offerings…”
Yet today, that place no longer exists.Numbers 3:10 –
“So you shall appoint Aaron and his sons, and they shall attend to their priesthood…”
But the lineage of Levi is no longer traceable.Deuteronomy 16:16 –
“Three times a year all your males shall appear before the Lord your God in the place which He chooses…”
Yet these feasts cannot be kept without the Temple.
The Law was tied to physical locations, the Levitical priesthood, and blood lineage — but all of these were lost after the destruction of Solomon’s Temple, later rebuilt under Nehemiah, and destroyed again. Even the best of Israel, including King David, were still corruptible men who decayed in death.
The author of Hebrews confirms the impermanence of Moses’ Law:
Hebrews 8:7 –
“For if that first covenant had been faultless, then no place would have been sought for a second.”Hebrews 10:1 –
“For the law, having a shadow of the good things to come… can never with these same sacrifices… make those who approach perfect.”
Thus, Moses’ Law was never meant to be permanent. It was a shadow, a pattern, a temporary covenant pointing forward to Christ.
2. The Incorruptible Heart of the Law
The Sermon on the Mount reveals the core theme Jesus wanted to restore: the heart behind the Law. The Jews were obeying the letter, but not the intent. Jesus exposes this:
Matthew 5:21–22 – They did not murder, but they harboured anger and hatred.
Matthew 5:27–28 – They avoided adultery outwardly but lusted in their hearts.
Matthew 5:31 – They abused the certificate of divorce for any reason.
Matthew 6:1 – They gave charitably, but for self-glorification.
Matthew 6:5 – They prayed in public for applause, not communion with God.
Matthew 7:1–5 – They judged others while ignoring the plank in their own eye.
They technically followed the Old Testament as they defined it — legalistic obedience without spiritual transformation. In modern examples: the difference between genuine charity and giving for publicity or political gain. The act may look similar; the heart is not.
Jesus came to restore this incorruptible heart:
Romans 8:3 –
“For what the law could not do in that it was weak through the flesh, God did…”Galatians 3:24–25 –
“Therefore the law was our schoolmaster to bring us to Christ… But after faith has come, we are no longer under a tutor.”Matthew 22:37–40 –
“‘You shall love the Lord your God with all your heart…’ On these two commandments hang all the Law and the Prophets.”
The Law was good — it pointed to God’s standard.
The people who crucified Jesus were the ones who kept the Law outwardly. Therefore, grace and faith had to take their place.
3. Justified by Faith
The Sermon on the Mount supersedes Moses’ Law because justification cannot come from works, only from faith in Christ.
Hebrews 10:1–4 teaches that sacrifices in the Old Testament were not able to take away sins:
“For it is not possible that the blood of bulls and goats could take away sins.”
If those sacrifices had worked, they would not have been repeated daily and yearly.Galatians 3:21 –
“If there had been a law given which could have given life, truly righteousness would have been by the law.”Romans 3:20 –
“By the law is the knowledge of sin.”
The Law reveals sin but cannot remove it from our lives.
Righteousness cannot be produced through law-keeping. It may tell us what is right and wrong, but it cannot change the sinner’s heart or save his soul. The weakness of the flesh makes “do and don’t” not possible.
We can only be justified and saved through faith in God and the grace He extends to us.
Ephesians 2:8–9 –
“For by grace you have been saved through faith… not of works, lest anyone should boast.”1 John 3:18 –
“Let us not love in word or in tongue, but in deed and in truth.”
True righteousness flows from a transformed heart.
Thus, salvation is not earned by works or rituals; it is received through faith and lived out in love.
Conclusion: Setting Our Hearts Right
The answer to “Why replace Moses’ Law with Jesus’ Sermon on the Mount?” is clear:
The decay of Moses’ Law – It became impossible to keep and was never meant to be permanent.
The incorruptible heart of the Law – Jesus restored the intent, not the letter.
Justified by faith – Only Christ can save; the Law could not.
Before we interpret any commandment, we must first set our heart and faith right. The Old Testament was a schoolmaster, but only God’s grace can save.
Micah 6:8
“He has shown you, O man, what is good;
And what does the Lord require of you
But to do justly,
To love mercy,
And to walk humbly with your God?”
The question for us today is: Do we have this same heart as the foundation of our faith?
May we live not just by rules, but by a transformed, Christ-shaped heart — walking humbly, loving mercy, and doing justice before the Lord.
