Ref: Hebrews 10:19.
Without Christ the holiness of God had to be protected from us. He would have been dishonored, and we would have been consumed because of our sin. But now, because of Christ, we may come near and feast our hearts on the fullness of the flaming beauty of God’s holiness. He will not be dishonored . We will not be consumed. Because of the all-protecting Christ, God will be honored, and we will stand in everlasting awe. Therefore, do not fear to come. But come through Christ.
Here’s something awesome I learned a little while back regarding the OT “shadows”. The New Jerusalem described in Revelation 21 is a cube. The only other cube mentioned in Scripture is the Holy of Holies/ Most Holy Place/ Inner Sanctuary in Solomon’s temple ( 1 Kings 6:20). So, the place where God dwelt with His chosen people in the OT was a shadow of a reality in heaven where God shall dwell with His people (hmmm.. even the wording in those two verses is similar. Compare also with Ezekiel 37:27). The difference is that back then, God’s presence with His people depended on their obedience, and in the New Jerusalem it all depends on Christ’s finished work at the cross.