“Whereof I am made a minister, according to the dispensation of God which is given to me for you, to fulfil the word of God” (Colossians 1:25).
With the Lord Jesus Christ directly revealing to Paul the Dispensation of Grace of God, we have a completed Bible. Hence, Paul wrote in his final epistle: “ All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:  That the man of God may be perfect, throughly furnished unto all good works” (2 Timothy 3:16,17).
The Apostle Peter preached in Acts 3:21 about that “which God hath spoken by the mouth of all his holy prophets since the world began.” In stark contrast, the Apostle Paul had a ministry concerned about “the preaching of Jesus Christ, according to the revelation of the mystery, which was kept secret since the world began, But now is made manifest” (Romans 16:25,26). These are two totally different dispensations, never to be confused unless we want to be confused. God kept a secret, but He revealed it directly and exclusively to Paul. Without Paul’s writings, Romans through Philemon, we lose the “household rules” God withheld from other Bible writers and holy men of old.
We see Paul as God’s spokesman to us—not Jesus in His earthly ministry, Peter, Moses, John the Baptist, and so on. We realize Jesus Christ exalted in Heaven (Paul’s ministry), not just on Earth (rest of Scripture). We know we are under Grace (Paul’s ministry), not under Law (rest of Scripture). We see the Gospel of the Grace of God—Christ’s finished crosswork as sufficient payment for our sins—as our way to a right standing before God (Paul’s ministry), not other Gospel messages (rest of Scripture). We recognize our completeness in Christ (Paul’s ministry), not needing rites and rituals and ceremonies to make God happy with us (rest of Scripture). We see ourselves as the Church the Body of Christ (Paul’s ministry), not the nation Israel (rest of Scripture). We recognize the difference between mystery (Paul’s ministry) and prophecy (rest of Scripture).
If we are to know God’s will for us today, we had better pay attention to His current “household rules”—Paul’s ministry and writings! source