Bible verses which warn about tampering with the Word of God

And now, O Israel, listen to the statutes and the rules that I am teaching you, and do them, that you may live, and go in and take possession of the land that the Lord, the God of your fathers, is giving you. You shall not add to the word that I command you, nor take from it, that you may keep the commandments of the Lord your God that I command you. (Deuteronomy 4:1-2)

Be careful to obey all these words that I command you, that it may go well with you and with your children after you forever, when you do what is good and right in the sight of the Lord your God…Everything that I command you, you shall be careful to do. You shall not add to it or take from it. (Deuteronomy 12:28,32)

Every word of God proves true; he is a shield to those who take refuge in him. Do not add to his words, lest he rebuke you and you be found a liar. (Proverbs 30:5-6)

In the beginning of the reign of Jehoiakim the son of Josiah, king of Judah, this word came from the Lord: “Thus says the Lord: Stand in the court of the Lord‘s house, and speak to all the cities of Judah that come to worship in the house of the Lord all the words that I command you to speak to them; do not hold back a word. It may be they will listen, and every one turn from his evil way, that I may relent of the disaster that I intend to do to them because of their evil deeds. (Jeremiah 26:1-3)

For I testify unto every man that heareth the words of the prophecy of this book, If any man shall add unto these things, God shall add unto him the plagues that are written in this book: And if any man shall take away from the words of the book of this prophecy, God shall take away his part out of the book of life, and out of the holy city, and from the things which are written in this book. (Revelation 22:18-19)