Have you ever noticed the wording of the majestic statement with which the Bible opens?
“In the beginning God created the heaven and the earth” (Gen. 1:1).
It does not say that God created “the universe,” but “the heaven” and “the earth.”
This is because God had a special purpose for the earth quite distinct from His purpose for the rest of the universe. This purpose concerning the earth and the nations to dwell upon it is progressively revealed in the Scriptures. We look forward to its glorious consummation when “the earth shall be full of the knowledge of the Lord, as the waters cover the sea” — when the Christ who was crucified here shall come into His right, reigning as King of kings and Lord of lords.
But God also had a very special purpose concerning heaven which He kept hidden in His own heart of love until man’s sin and rebellion had reached their climax. Then He stooped down, saved the “chief of sinners” and used him to make known the wondrous secret of His purpose to offer to sinners everywhere, salvation by grace through faith alone, reconciling them to Himself in one body by the cross and giving them a present position and a future prospect in the highest heavens.
God’s purpose concerning the earth and Christ’s reign upon it is the subject of prophecy (Luke 1:68-76), His purpose concerning heaven and our exaltation there with Christ is the subject of “the mystery” (Eph. 2:4-10; 3:1-4). Into these two great subjects the Scriptures are basically divided. source