Speaking of the doctrinal escape-hatch of “mystery” that Calvinists often use when mitigating against their own inevitable, theological contradictions, Keith Schooley explains:
Other examples of mysteries are Revelation 10:4 and Revelation 17:5:
“When the seven peals of thunder had spoken, I was about to write; and I heard a voice from heaven saying, ‘Seal up the things which the seven peals of thunder have spoken and do not write them.’”
“On her forehead a name was written, a mystery, ‘Babylon the Great, The Mother of Harlots and of the Abominations of the Earth.’”
In both cases, we do not have a theology contradiction at hand, but mysteries that await revelation.