yes- for Israel only. gentiles were never under the law.
Gentiles are now grafted in (Romans 11)
You are indeed "UNDER THE LAW" if you break it.
ROMANS 3 [19], Now we know that whatsoever things the law says, it says to them who are UNDER THE LAW: that every mouth may be stopped, and all the world may become guilty before God. [20], Therefore by the deeds of the law there shall no flesh be justified in his sight: for by the law is the knowledge of sin.
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Only God's Word is true dear and we should BELIEVE and FOLLOW it over the traditions of men that break the Commandments of God.
SIN is the breaking of God's Commandments (James 2:9-11; Romans 7:7; 1 John 3:4)
Those who CONTINUE in UNREPENTANT SIN will NOT enter into the KINGDOM of HEAVEN.
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God's 4th commandment is one of the ten (Exodus 20:8-11) If we knowingly break it when God asks us not to we stand guilty before God of committing sin (James 2:8-12). If we do not seek him in repentance and forgiveness we are in danger of the Judgement (Hebrews 10:26-27)
Sunday worship is a tradition and teaching of man that has led many to break the commandments of God. Jesus says that if we follow the traditions of man that break the commandments of God we are not following God (Matthew 15:3-9)
There is not one scripture in all of God's Word that says that God's 4th Commandment is now ABOLISHED and we are now commanded to KEEP Sunday as a Holy day.
Who should we follow the teachings and traditions of men or the Word of God? Who should we believe the Words of men or the Word of God?
In times of ignorance God winks at but now ,<when a KNOWLEDGE of the truth has come> calls all men everywhere to REPENT (FOLLOW) (Acts 17:30-31).