Galatians 4:26 But the Jerusalem above is free, and she is our mother.
Many of us believe that the Heavenly Jerusalem is indeed the church, with Jesus the head of that church. The church is of course made up of all who believe. Not some earthly organization.
The metaphor that Paul uses is to distinguish between the child of the slave, and the child of the free.
However, the mother metaphor is taken to an extreme by some to include the earthly organizations, and that, as our mother, we must obey it without question.