What does it mean to be, under the law?
Romans 3:19 Now we know that whatever the law says, it says to those who are under the law, that every mouth may be stopped, and all the world may become guilty before God.
The law here is referring to the ten commandments, which were added 430 after the promise of having a son was made to Abraham.
Galatians 3:16-17 The promises were spoken to Abraham and to his seed. Scripture does not say “and to seeds,” meaning many people, but “and to your seed,” meaning one person, who is Christ. What I mean is this: The law, introduced 430 years later, does not set aside the covenant previously established by God and thus do away with the promise.
Why was the law added?
It was added because of sin.
Galatians 3:19 Then why do we have the Law? It was added because of sin. It was to be used until Christ came. The promise had been made, looking toward Christ. The Law was given by angels through Moses, who stood between God and man.
The law that was added because of sin is what demanded the imposed death penalty, i.e., you sin, you get stoned to death. This way of God dealing with sin was not in effect prior to the giving of the law at Mt. Sinai.
Romans 5:12-14 When Adam sinned, sin entered the world. Adam’s sin brought death, so death spread to everyone, for everyone sinned. Yes, people sinned even before the law was given. But it was not counted as sin because there was not yet any law to break. Still, everyone died—from the time of Adam to the time of Moses—even those who did not disobey an explicit commandment of God, as Adam did. Now Adam is a symbol, a representation of Christ, who was yet to come.
The law at Sinai quickly brought God’s imposed punishment for sin, but sin itself has its own deadly consequence, even without being under the law at Sinai.
Romans 2:12-13 When the Gentiles sin, they will be destroyed, even though they never had God’s written law. And the Jews, who do have God’s law, will be judged by that law when they fail to obey it. For merely listening to the law doesn’t make us right with God. It is obeying the law that makes us right in his sight.
When we sin under the law, we also break the law.
1 John 3:4 Everyone who commits sin also breaks the law; sin is the breaking of law.
If we are no longer under the law, but under grace, it means we no longer receive God's imposed punishment for sin i.e. stoning to death, but this does not mean we can now sin without a consequence. Remember, sin and death was in the world even before the law was given at Mt. Sinai.
Romans 6:15 What then? Shall we sin because we are not under law but under grace? Certainly not!
Why are we commandment not to sin? Because sin itself will still kill us, even without the law that was given at Mt. Sinai. Take away the law, and sin still remains, there's just no immediate consequence for sin, i.e. stoning to death. For example, violating the Sabbath. Under the law, if you violate the Sabbath, there is an immediate consequence under the law.
Exodus 31:15 Work shall be done for six days, but the seventh is the Sabbath of rest, holy to the Lord. Whoever does any work on the Sabbath day, he shall surely be put to death.
The law didn’t invent sin, the law only pointed it out and then demanded a quick sentence, i.e. stoning. Remember, sin had its own death sentence even without the law, which was enacted 430 years later at Mt. Sinai.
Romans 5:12-14 When Adam sinned, sin entered the world. Adam’s sin brought death, so death spread to everyone, for everyone sinned. Yes, people sinned even before the law was given. But it was not counted as sin because there was not yet any law to break. Still, everyone died—from the time of Adam to the time of Moses—even those who did not disobey an explicit commandment of God, as Adam did.
The ten commandments are only a summarization of the Torah. The Torah is the foundation from which we build and draw our doctrines, even without the law given at Mt. Sinai.
When you read the next verses I want you to notice how from their childhood, they studied the Scriptures and how the Scriptures are to be used for doctrine, correction and instruction in righteousness. This is the Old Testament they are referring to here because they didn’t have the New Testament from their childhood, they didn’t even have the New Testament when they were saying this.
2 Timothy 3:15-17 from childhood you have known the Holy Scriptures, which are able to make you wise for salvation through faith which is in Christ Jesus. All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness, that the man of God may be complete, thoroughly equipped for every good work.
Today’s church doctrines cannot be taught using the OT Testament because they are rooted in Babylon, not the Torah or the Prophets. Doctrines such as Sunday worship, immortal soul, eternal burning in hell, the dead are alive, Christmas, Easter, Good Friday and so on are not found in the Torah or the Prophets, they're not even found in the New Testament.
If you worship the God of Israel and live according to the Torah and the Prophets, you will be called a cult by mainline churches today.
Acts 24:14 But I confess this to you, that I worship the God of our ancestors according to the Way, which they call a cult, believing everything that is according to the law and that is written in the prophets.
If we are to love and worship God and love our neighbor in a godly way, we must follow the Torah and the Prophets as taught by Jesus because the Torah and the Prophets hang on the way we define love for God and love for our neighbor.
Matthew 22:37-40 And Jesus said to him, “‘You shall love the Lord your God with all your heart, and with all your soul, and with all your mind.’ This is the first and greatest commandment. And the second is like it, ‘You shall love your neighbor as yourself.’ The entire Torah and the Prophets hang on these two commandments.”