Apostolic succession is the unbroken traceable line of ordination and doctrine from the Apostles to the current Church. This succession in the Orthodox Christian Church manifests itself through the unbroken succession of its bishops back to the apostles. The Orthodox Church, through apostolic succession, ensures the teachings of the Apostles and their immediate successors remain formally intact from generation to generation.
Orthodox teachings today are the same as that of the first Apostles. Although their mode of expression has adapted over the centuries, the spiritual truths have not changed. Since the identity of the original Apostles is known, as is the content of their teachings, anyone teaching anything contrary is not transmitting the authentic truth.