Paul told the Galatians, “I am astonished that you are so quickly deserting him who called you in the grace of Christ and are turning to a different gospel” (Gal 1:6).
Two observations about this verse:
(1) The phrase “him who called you” refers to God the Father.
(2) They are (literally) “turning from” the Father “to another gospel.”
Now we can draw three conclusions:
(1) Other religious messages do not lead to more knowledge of God.
(2) Turning to other gospels is simultaneously desertion from God, or apostasy–because other gospels aren’t actually legitimate (1:7a).
(3) If the Father called them in the grace of Christ, then turning away from God is also a departure from His grace.
Underlying Paul’s concern is this truth: other gospels aren’t legitimate messages that save sinners but, instead, are deceptive messages that distort the way of salvation, lead away from a true knowledge of God, and substitute a system of works for divine grace.
Like the Galatians, we need the reminder to hold to the biblical gospel about the grace of God displayed in the cross of Christ on behalf of sinners.