The term “mystery” as used in Scripture denotes the fact that the Lord has revealed a particular thing but kept hidden the significance of that particular tidbit of revelation till a later date (Ephesians 3:4–6). Through telling us that the name of this woman is a “mystery,” the Holy Spirit clues us in to the fact that this woman had been hinted at in the Old Testament but the full depth of that revelation was not made clear till now. That is why if we are to understand her name well, we need to go back to the Old Testament and read again the opaque outlines concerning Babylon in light of what’s clarified here.
5 And on her forehead was written a name of mystery: “Babylon the great, mother of prostitutes and of earth’s abominations.”