These two phrases, "Mystery of Godliness" and "Mystery of Iniquity" occur only once each in scripture. The mystery of iniquity would be a counterfeit to the mystery of Godliness in this world.
And without controversy great is the mystery of godliness: God was manifest in the flesh, justified in the Spirit, seen of angels, preached unto the Gentiles, believed on in the world, received up into glory. 1 Timothy 3:16
For the mystery of iniquity doth already work: 2 Thessalonians 2:7