Paul speaks of these mountains in Galatians 4. Mount Sinai produces children of slavery, but our mother, the Jerusalem above, is in the heavens, at Mount Zion (vv. 25-26). Revelation 14:1 tells us that there are a hundred and forty-four thousand standing with the Lamb on Mount Zion. These hundred and forty-four thousand are not praising God for the law given at Mount Sinai. Mount Zion is not a place to show us the law, the commandments. It is a place to show us Christonly Christ. Mount Sinai is in the Bible, but the spirit of the Bible does not exalt it. Instead, the Bible puts Mount Sinai down to a lower place. The spirit of the Bible exalts only Christ.
The sad thing is that many of God's chosen people forget about Christ. They believe in Christ, but they do not know Christ or care for Christ. Instead, they care for the law. Paul said, "For to me, to live is Christ" (Phil. 1:21a). We might say, "For to me to live is yes and no, good and evil, right and wrong." What mountain are we on today? Nearly all of us are on Mount Sinai. We are not disciples of Moses but disciples of Christ. However, we are on the wrong mountain. Christ is on Mount Zion. He is not on Mount Sinai, but we still linger there. Many of us dare not say good-bye to the law. Instead, we want to stay with the law as a follower of David, meditating in the law day and night.
We need to see that the entire revelation of the Bible is progressive. The revelation in the holy Word proceeds higher and higher from Genesis to its peak in Revelation. Genesis 1 speaks of God's creation, but Revelation 22 speaks of the New Jerusalem. God's creation is somewhat easy to understand, but the sign of the New Jerusalem is a great mystery. The revelation of the New Jerusalem is high and profound to the uttermost.
The five books of the Psalms were arranged in the same progressive way as the entire Bible was arranged. From the first book of the Psalms to the fifth book, the revelation proceeds higher and higher. The fifth book is full of the psalmists' praising of God. God is embodied in Christ, Christ is in His Body, and His Body is God's house and God's city for God's kingdom. This is all for God's economy. The central thought of the book of Psalms is Christ and the church as the house of God and the city of God for His kingdom.