giving vengeance to those who don't know God, and to those who don't obey the Gospel of our Lord Jesus,
This phrase "that obey not the gospel" refers equally to unbelievers of every race and from every nation. It shows that those who refuse to obey the gospel plan of salvation extended by Jesus Christ will be lost. This part of the gospel is best described in Mark 16:15-16 and Romans 6:3-6 where everyone is instructed to be baptized in order to be saved. James Burton Coffman says: