The Jerusalem above is free, and she is our mother, Galatians 4:26
The passage above occurs in the context of Paul making the case of the Church being superior to Judaism, most specifically in the way of faith's superiority to the Law of Moses. The Jerusalem above is contrasted with "the present Jerusalem" (v. 25). But what do we learn from Paul's use of the term, "mother" in this context?
The early Church appropriated many of the terms used in the writings of the Old Testament. Jerusalem stands in for the Church, as we read in another context, I saw the holy city, new Jerusalem, coming down out of heaven from God, prepared as a bride adorned for her husband, (Rev. 21:2). By referring to the Church as our mother, Paul is directing our attention to the place of the Church in our lives.
The Church nourishes us and guides us in the teaching of the Word and the giving of the Sacraments. She is truly our Mother in that she cares for us. The Church is fleshed out for us in the bishops. They are the ones entrusted with the teaching office of the Church. All of the bishops together in union with the Pope constitute for us what is known as the Magisterium. They are the ones we look to for definitive statements regarding faith and morals. For any question, we go to our Mother.
Paul states elsewhere that the Church is the pillar and bulwark of the truth, (1 Tim. 3:15). This means that the Church is infallible. She is looked to for truth. So she must be visible. People need to know where they can go to find the truth. They find it in the Church. For the Church teaches only what was given to her by Christ, who is Himself, the way, and the truth, and the life, (Jn. 14:6).
Unfortunately, too many people believe otherwise. Instead of listening to the sure guide of the Scriptures, they choose to listen to their favorite Bible teachers interpret the Scriptures. They forsake the Church and then invent something new to take its place. They refer to their own churches, but what authority do they have? What credibility do they have? They all teach different from what was believed from the beginning.
Only the Catholic Church teaches in fullness what was given from the beginning. That is why we can confidently look to her as our Mother. She can be trusted. She can be followed. She will guide us safely home to eternal life.