THERE REALLY ARE TWO GOSPELS

To explain, Apprising Ministries points you to this audio clip from pastor Steve Lawson at the 2009 Shepherds’ Conference:

Paul is completely astounded and amazed. Why? That they should abandon the gospel so quickly that he had brought to them. To abandon meant to go AWOL — they were deserting at this very hour the person of Christ Himself.

They are not only deserting the gospel, but note that he says they are deserting God Himself. They were deserting God who Himself is the gospel. There is solidarity between God and the gospel. This is Gods message. To abandon the message is to abandon God Himself. Every attribute of God is seen in the Gospel most brilliantly.

If Gods glory is put on display in his creation, it is put on even greater display in the gospel. At the cross we see sin, holiness, Christ in all His glory, the torment of the damned in the cry of Christ, the righteousness of Christ in the life and obedience of Christ, the grace of God providing righteousness for sinners, the immutability of God in one unchanging way of the gospel, the power of God to save the chief of sinners, the truth of God, the sovereignty of God saving all His elect — God is the gospel and to depart from the gospel is to depart from God Himself. All the lines of theology proper intersect with the gospel itself and the person of Christ who is the gospel for us.

who called you by the grace of Christ = You are deserting Him after He has done this??? After making them trophies of His grace, they are doing this???

You are turning to another gospel = there are only two kinds of gospel — the true gospel and the false gospel of human achievement. This different (heteros) gospel denotes another of a completely different kind. It is non-saving and non-sanctifying. It was a rip-off religion to which they were turning. Any other message apart from Christ is a soul-damning message.

To desert this gospel is to be removed from the only way of salvation.

Paul was amazed that the Galatians were deserting this one true saving gospel. And we too should be amazed when people sign ECT and pretend there is no distinction between Rome and the gospel. (source)

Further reading