Only be strong and very courageous, to observe to do according to all the law, which Moses my servant commanded thee: turn not from it to the right hand or to the left, that thou mayest have good success whithersoever thou goest. Joshua 1:7 ASV
The Jewish Bible which the Christians call 'The Old Testament' is a SCIENCE. She is the most rigid Science in that she is unchangeable, immutable, uncompromising just as her Author YHWH Elohim changes not. Such knowledge of this science makes us act wisely for salvation fending off all the false prophets who are to lead many astray according to prophecy. Only YHWH may change something in her. YHWH will not give an order to anyone or any Angel in Heaven to promulgate a change in her. From Moses to Jesus, there was no one who could have changed anything in her.
Today, we have to be more vigilant because the Adversary may not faithfully transmit the intent of the original message in the translation.
And many false prophets shall arise, and shall lead many astray. Matthew 24:11 ASV
(1) But there arose false prophets also among the people, as among you also there shall be false teachers, who shall privily bring in destructive heresies, denying even the Master that bought them, bringing upon themselves swift destruction. 2 Peter 2:1-3 ASV
And thine eyes shall not pity; life shall go for life, eye for eye, tooth for tooth, hand for hand, foot for foot. Deuteronomy 19:21 ASV
(38) Ye have heard that it was said, An eye for an eye, and a tooth for a tooth: (39) but I say unto you, Resist not him that is evil: but whosoever smiteth thee on thy right cheek, turn to him the other also. Matthew 5:38-39 ASV
And she said, No man, Lord. And Jesus said, Neither do I condemn thee: go thy way; from henceforth sin no more. John 8:11 ASV
A new commandment I give unto you, that ye love one another; even as I have loved you, that ye also love one another. John 13:34 ASV