Deuteronomy 4:2 Do not add to what I command you and do not subtract from it, but keep the commands of the LORD your God that I give you.
1 Corinthians 15:1-4
1 Now, brothers, I want to remind you of the gospel I preached to you, which you received and on which you have taken your stand.2 By this gospel you are saved, if you hold firmly to the word I preached to you. Otherwise, you have believed in vain. 3 For what I received I passed on to you as of first importance : that Christ died for our sins according to the Scriptures,4 that he was buried, that he was raised on the third day according to the Scriptures.
22 Do not merely listen to the word, and so deceive yourselves. Do what it says.23 Anyone who listens to the word but does not do what it says is like a man who looks at his face in a mirror 24 and, after looking at himself, goes away and immediately forgets what he looks like. 25 But the man who looks intently into the perfect law that gives freedom, and continues to do this, not forgetting what he has heard, but doing it–he will be blessed in what he does.
[Jesus said] 48 There is a judge for the one who rejects me and does not accept my words; that very word which I spoke will condemn him at the last day.49 For I did not speak of my own accord, but the Father who sent me commanded me what to say and how to say it.50 I know that his command leads to eternal life. So whatever I say is just what the Father has told me to say.”
2 Corinthians 4:2-5
2 We have renounced secret and shameful ways; we do not use deception, nor do we distort the word of God. On the contrary, by setting forth the truth plainly we commend ourselves to every man’s conscience in the sight of God.3 And even if our gospel is veiled, it is veiled to those who are perishing.4 The god of this age has blinded the minds of unbelievers, so that they cannot see the light of the gospel of the glory of Christ, who is the image of God.5 For we do not preach ourselves, but Jesus Christ as Lord, and ourselves as your servants for Jesus’ sake
1 Many have undertaken to draw up an account of the things that have been fulfilled  among us,2 just as they were handed down to us by those who from the first were eyewitnesses and servants of the word.3 Therefore, since I myself have carefully investigated everything from the beginning, it seemed good also to me to write an orderly account for you, most excellent Theophilus,4 so that you may know the certainty of the things you have been taught.
2 Peter 1:21 For prophecy never had its origin in the will of man, but men spoke from God as they were carried along by the Holy Spirit.
15 Bear in mind that our Lord’s patience means salvation, just as our dear brother Paul also wrote you with the wisdom that God gave him.16 He writes the same way in all his letters, speaking in them of these matters. His letters contain some things that are hard to understand, which ignorant and unstable people distort, as they do the other Scriptures, to their own destruction.
2 Timothy 3:14-16
14 But as for you, continue in what you have learned and have become convinced of, because you know those from whom you learned it,15 and how from infancy you have known the holy Scriptures, which are able to make you wise for salvation through faith in Christ Jesus.16 All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness.
Hebrews 4:12 For the word of God is living and active. Sharper than any double-edged sword, it penetrates even to dividing soul and spirit, joints and marrow; it judges the thoughts and attitudes of the heart.