The Galatians must learn to distinguish between friend and foe, for confusion about this leaves them in danger of harm from the one, and deprives them of the help and comfort of the other. The Judaizers had found their way into the hearts of the Galatians and they were taking full advantage of their position.
Few Christians scrutinise every doctrine that comes to them with equal care; we instead consider its source, for it is hard to be constantly applying the same rigorous test to all. We lower the barriers to those we trust and allow their teaching and influence to enter our hearts where it is free to modify attitudes and shape our ideas. Those who try to influence us expect to see trust developing in us, and it is offensive to them if we never lower our guard however long we have known them. However, without being overly suspicious, we should always make our first loyalty to the Lord and his word.