Mother God is the Rock

So I'm getting to go a little more in depth in my studies at the World Mission Society Church of God. Just finished learning that God the Mother is the Rock in the bible. Actually I never knew anything about this, nor did I even hear mentions of the rock in the bible. Of course, I didn't know anything even though I thought I knew something before. In the book of Isaiah 44:8, God Himself says He is the "only" rock and besides Him there is no other rock. Through this I realized that the only rock in the bible is God Himself. That's clear, but what shocked me most was the last verse as always. In the book of Zechariah 12:3 it says "On that day, when all the nations of the earth are gathered against her, I will make Jerusalem an immovable rock for all the nations. All who try to move it will injure themselves."
The same bible that says God is the only rock says that in the last days, Jerusalem will be an immovable rock. Who is Jerusalem? Galatians 4:26 says "but the Jerusalem that is above is free and she is our MOTHER". Once again it is made clear to me that the reason the members of the Church of God World Mission Society boldly proclaim the existence of Heavenly Mother is because She's truly found in all parts of the bible. Thanks for reading. I'll keep you posted with more studies I learn.