Does not Christianity today differ vastly from the religion Christ preached?

The Catholic Answers

Outside the Catholic Church, yes. But in the Catholic Church the exact religion of Christ has come down to us in virtue of Christ’s promise to be with His Church all days till the end of the world. This assertion will be justified in a later section.

Radio Replies Volume 1 by Rev. Dr. Leslie Rumble MSC and Rev. Charles Mortimer Carty