Mother Jerusalmem Is Not a New Teaching In the Bible

Some people say that the belief in Mother Jerusalem is based on some religion, or denomination. Actually, any denomination is a religion and "form" of Christianity.

I really don't understand if a denomination is supposed to follow Christianity, but they don't follow Christ, how are they still considered Christian. If a person claims to be Buddhist, but does not follow Buddah, are they still considered Buddhist?

Why is it different for Christianity? 2000 years the Apostles, on whom the fundation of the church was built, what did they believe?

Gal. 4:26 "But the Jerusalem that is above is free, and she is our mother."

They believed in the Jerusalem above (heaven) as Mother God. Think about the Father above; isn't He God? Then what about the Mother above? Shouldn't our faith and belief and faith as Christians be the same?