6 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. — Galatians 1:6,7 KJV
allos adj def another of the same kind; another of a similar type.
heteros adj def another of a distinct different kind; stands in contrast to
pronounced al’-los or het’-er-os
In Galatians 1:6,7 Paul is astounded that the Galatian Christians were turning to a heteros gospel. This gospel is not only distinct in character from the gospel he preached, it was essentially evil. There cannot be a “good news” that is different from the gospel of Christ that Paul preached. There is not allos gospel at all. The salvation-by-works which the Galatians were turning to was false — diametrically opposed to the gospel they had received from Paul. Therefore, the “good news” was not good at all.
Salvation-by-works leads to everlasting death, whereas salvation-by-grace through faith in the finished work of Christ is (not leads to — that life begins at the moment of trusting in Jesus) everlasting life.