When the Bible speaks about a mystery, it speaks of something that cannot be known by human comprehension. It can only be known if it is revealed by God. The mystery of godliness is the mystery of Christ. It’s a mystery that man could have never thought of.
When Paul mentions the mystery of godliness, he doesn’t mention anything about us, the ones who have been made godly, he brings it back to Christ.
The church is the pillar and buttress of the truth; and if we’ve been entrusted with this truth about Christ, the mystery of godliness, we need to proclaim it as it is. We need to proclaim the supernatural mystery of godliness to this world that depends so much and thinks so highly of their science and knowledge. Is your Christianity miraculous and mysterious? It doesn’t matter what your intellect and educational background is, or how smart you are. It matters whether or not God has revealed this mystery to you.