Biblical explanation
Hebrews 1:1 gives an important overview: "God, who at sundry times and in divers manners spake in time past unto the fathers by the prophets." Hebrews 1:1, KJV God communicated through different prophets and at different times. The Old Testament contains writings associated with the history of Israel, beginning with Moses and continuing through the prophets. The New Testament was written during the apostolic era following the earthly ministry, death, resurrection, and ascension of Jesus. Paul's letters were already circulating among churches during the apostolic period (Colossians 4:16), while Peter referred to Paul's writings alongside "the other scriptures" (2 Peter 3:15-16). The Bible does not give a complete modern-style publication history. Therefore, exact dates for individual books belong to the field of historical and textual study rather than something that can always be established directly from Scripture. What Scripture clearly shows is that God's revelation was given progressively through many prophets and eventually centered in the revelation of His Son: "Hath in these last days spoken unto us by his Son." Hebrews 1:2, KJV
Key takeaway
The great controversy reveals God's character as Christ ministers as our High Priest in the heavenly sanctuary. The dead await the resurrection, Christ's return will be visible and personal, and prophecy calls believers to faithful mission rather than date-setting or fear.