"What's the old gospel then?"
Good question, zn. It is what The Church always and everywhere believed; it is the Faith of The Church of the Seven Councils. I'll give you an example of what I mean.
In the 7th century a terrible heresy, Monothelitism, arose which denied the two natures of Christ, asserting that Christ had only one will, a divine one. This heresy was subscribed to by the Emperor, the Patriarch of Constantinople and a large number of the other hierarchs, clergy and laity in The Church. One man, +Maximos the Confessor, among all the Christians opposed to this heresy, stood forth and suffered grievously for his adherence to The Faith. When it was pointed out to him that all the Patriarchs of the East maintained communion with the heretical Patriarch of Constantinople, that even the legates of the Pope served with him, he replied:
"Even if the whole universe holds communion with the patriarch, I will not communicate with him. For I know from the writings of the holy Apostle Paul: the Holy Spirit declares that even the angels would be anathema if they should begin to preach another Gospel, introducing some new teaching."
The Monothelite heresy was eventually condemned in 680, 18 years after +Maximos died, at the 6th Ecumenical Council, which, by the way, anathemized that Patriarch as a heretic.
Exactly so: and I ask, has Eckleburg preached another Jesus?