Read: Galatians 1:3-10
The American cities San Francisco and New York City are using bluegill fish to check for the presence of toxins in their water supply, which could be a possible target for a terrorist attack. A small number of bluegills are kept in a tank at the bottom of some water treatment plants because the fish are sensitive to chemical imbalances in their environment. When a disturbance is present in the water, the bluegills react against it.
Like those bluegills, Paul the apostle wanted the Galatians to beware of and react against any deviation or disturbance in the “true gospel” that was being preached. The toxin was defined as the false principle that God grants acceptance to people and considers them righteous on the basis of their obedience to a set of rules (circumcision and dietary regulations). Obedience to the law was needed for salvation, apart from faith in Jesus. This false teaching was a poison or toxic disturbance of the truth and the Galatians were told to react strongly against it. Paul said that anyone preaching a gospel that is not based on grace through faith in Christ alone should be accursed (Gal. 1:8-9).
Let us be diligent and faithful in studying the Scriptures so that we can detect the false teachings and their dangers, and proclaim the truth of God’s wonderful salvation through faith in Jesus. If you know the truth, you can discern what is false.