Deuteronomy 4:2
You must not add to or subtract from what I command you, so that you may keep the commandments of the LORD your God that I am giving you.

Revelation 22:18-19
I testify to everyone who hears the words of prophecy in this book: If anyone adds to them, God will add to him the plagues described in this book. / And if anyone takes away from the words of this book of prophecy, God will take away his share in the tree of life and the holy city, which are described in this book.

Deuteronomy 12:32
See that you do everything I command you; do not add to it or subtract from it.

Matthew 15:3-9
Jesus replied, “And why do you break the command of God for the sake of your tradition? / For God said, ‘Honor your father and mother’ and ‘Anyone who curses his father or mother must be put to death.’ / But you say that if anyone says to his father or mother, ‘Whatever you would have received from me is a gift devoted to God,’ ...

Galatians 1:6-9
I am amazed how quickly you are deserting the One who called you by the grace of Christ and are turning to a different gospel— / which is not even a gospel. Evidently some people are troubling you and trying to distort the gospel of Christ. / But even if we or an angel from heaven should preach a gospel contrary to the one we preached to you, let him be under a curse! ...

2 Peter 3:16
He writes this way in all his letters, speaking in them about such matters. Some parts of his letters are hard to understand, which ignorant and unstable people distort, as they do the rest of the Scriptures, to their own destruction.

Jeremiah 23:16
This is what the LORD of Hosts says: “Do not listen to the words of the prophets who prophesy to you. They are filling you with false hopes. They speak visions from their own minds, not from the mouth of the LORD.

2 Corinthians 11:3-4
I am afraid, however, that just as Eve was deceived by the serpent’s cunning, your minds may be led astray from your simple and pure devotion to Christ. / For if someone comes and proclaims a Jesus other than the One we proclaimed, or if you receive a different spirit than the One you received, or a different gospel than the one you accepted, you put up with it very easily.

Isaiah 8:20
To the law and to the testimony! If they do not speak according to this word, they have no light of dawn.

1 Timothy 6:3-5
If anyone teaches another doctrine and disagrees with the sound words of our Lord Jesus Christ and with godly teaching, / he is conceited and understands nothing. Instead, he has an unhealthy interest in controversies and disputes about words, out of which come envy, strife, abusive talk, evil suspicions, / and constant friction between men of depraved mind who are devoid of the truth. These men regard godliness as a means of gain.

Jeremiah 23:28-32
Let the prophet who has a dream retell it, but let him who has My word speak it truthfully. For what is straw compared to grain?” declares the LORD. / “Is not My word like fire,” declares the LORD, “and like a hammer that smashes a rock?” / “Therefore behold,” declares the LORD, “I am against the prophets who steal from one another words they attribute to Me.” ...

1 John 4:1
Beloved, do not believe every spirit, but test the spirits to see whether they are from God. For many false prophets have gone out into the world.

2 Timothy 3:16-17
All Scripture is God-breathed and is useful for instruction, for conviction, for correction, and for training in righteousness, / so that the man of God may be complete, fully equipped for every good work.

Matthew 5:17-19
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. / For I tell you truly, until heaven and earth pass away, not a single jot, not a stroke of a pen, will disappear from the Law until everything is accomplished. / So then, whoever breaks one of the least of these commandments and teaches others to do likewise will be called least in the kingdom of heaven; but whoever practices and teaches them will be called great in the kingdom of heaven.

Acts 17:11
Now the Bereans were more noble-minded than the Thessalonians, for they received the message with great eagerness and examined the Scriptures every day to see if these teachings were true.