The Pure Doctrine of the Gospel, by Dr. Ian Brown
The text for this sermon is Galatians 1:6-12 (Audio):
"I marvel that ye are so soon removed from him that called you into the grace of Christ unto another gospel: 7
Which is not another; but there be some that trouble you, and would pervert the gospel of Christ.8
But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed.9
11But I certify you, brethren, that the gospel which was preached of me is not after man.12
For I neither received it of man, neither was I taught it, but by the revelation of Jesus Christ."