The divine revelation in the Bible is progressive. In Genesis 1 we have a history of God's creation, but in that chapter we cannot see much of the divine revelation. Of course, there is some revelation there. For instance, verse 1 says, "In the beginning God created..." The Hebrew word for "God" here is Elohim, which means the "faithful, mighty One." From this word we can realize that God is faithful and also mighty. Furthermore, this word, a proper noun, is not singular but plural; however, the predicate "created" is singular. This is an indication that God is triune, three-one. This surely is something of the divine revelation that progresses throughout the Bible until the last chapter of Revelation.
In Colossians 1:25 Paul tells us that the stewardship of God was given to him "to complete the word of God." The word of God is the divine revelation, which had not been completed before the New Testament was written. In the New Testament the apostles, especially Paul in his fourteen Epistles, completed the word of God. It is clear, therefore, that the word of God had not been completed at the time of Job or David or Malachi or even at the end of the book of Acts.
Some mistakenly think that orthodox doctrine consists only of what the Lord Jesus taught the twelve apostles. Those who hold this concept need to consider the Lord's word in John 16:12-15: "I have yet many things to say to you, but you cannot bear them now. But when He, the Spirit of reality, comes, He will guide you into all the reality; for He will not speak from Himself, but what He hears He will speak; and He will declare to you the things that are coming. He will glorify Me, for He will receive of Mine and will declare it to you. All that the Father has is Mine; for this reason I have said that He receives of Mine and will declare it to you." The disciples had to wait for the Holy Spirit as the Spirit of reality to reveal more things to them. From this we see that the word of God had not been completed even when the Lord Jesus was on earth, but still needed to be completed through the speaking of the Spirit of reality. Surely Paul was a person to whom the Holy Spirit revealed many things, and he wrote concerning these things in his Epistles, indicating, as we have seen, that he had been commissioned by God to complete the word of God.
In particular, Paul completed the word of God in regard to the mystery of God, which is Christ (Col. 2:2), and the mystery of Christ, which is the church (Eph. 3:4). In Colossians 1:27 he says, "To whom God willed to make known what are the riches of the glory of this mystery among the Gentiles, which is Christ in you, the hope of glory." There is not such a word in Genesis or in the Psalms or fully in the four Gospels. This is an example of the fact that the divine revelation in the Bible is progressive and that it is not completed until the end of Revelation.