The whole Bible has been inspired by God, unlike the gnostic heretical gospels. For Paul said all Scripture is God-breathed (literally breathed into the minds of the apostles by the Holy Spirit) (2 Tim. 3:16). Furthermore, Paul gave a warning to the Corinthian church in 2 Cor. 13:2-3, "I already gave you a warning when I was with you the second time. I now repeat it while absent: On my return I will not spare those who sinned earlier or any of the others, 3 since you are demanding proof that Christ is speaking through me. He is not weak in dealing with you, but is powerful among you." Moreover, Peter said about Paul's writings, "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 Pet. 3:15-16) (NIV).
Therefore, Christians obey the words of Jesus, Peter, Paul, James and John, equally.