In my boyhood church, we called one another "Brother" and "Sister". This is now archaic, and I try to avoid it, but sometimes I slip and it comes out. The wording is out of style, but the lesson behind it never grows old.
We are all sibling-pupils in one school with one curriculum and with one Teacher. Ignatius described the Ephesians as his "schoolmates".
Do honor Pastors and teachers. They are to be loved and respected (1 Thess. 5:12-13). But remember they are only brothers. Human teachers are but conduits through which ultimate truth from the ultimate Teacher flows.
The thought of our being siblings is a great picture of the equality we have as believers. It refers to Christians, but has spilled over in Western Culture as an ideal extending to all. We believe all are created equal, and thus each person should have equal standing before the law.