God the Mother - Mystery of God

According to a chart I found online 33% of the World Population are Christians. That's 1/3rd of the Earth's habitants.
However, among all these Christians, I can confidently say that less than 2 Million know the truth about God. This is already proven through the Bible.

Col 2:2 My purpose is that they may be encouraged in heart and united in love, so that they may have the full riches of complete understanding, in order that they may know the mystery of God, namely, Christ, in whom are hidden all the treasures of wisdom and knowledge.

Why does the Bible say that Christ is a mystery?
What's so mysterious about Christ?
Anyone can simply pick up a Bible and read. At least that's what most Christians do, and this is why they say "I have a personal relationship with Jesus". Then what about this verse? We can't say the Bible is wrong and insist in our own opinion. We must know and understand what this means.

2 Cor 4:4 "The god of this age has blinded the minds of unbelievers, so that they cannot see the light of the gospel of the glory of Christ, who is the image of God.

That is the Mystery of Christ = The Image of God (Gen 1:26,27).
The mystery is that God is not only Male but also Female. the Male image of God we call God our Father (Heb 12:9) and the Female image of God, God our Mother (Gal 4:26).

Only in Zion, Church of God World Mission Society we know about the Heavenly Mother Jerusalem. Just like the Old Testament testified about Jesus Christ so the Old and New Testament testify about Heavenly Mother.