E know that we were not born morally qualified for heaven. We also know that there is no amount of personal sacrifice, ritual or devotion that is enough to bring us up to God's perfect standard. However, there is one qualifying trait that God demands for us to become His children. We must trust Him (Hebrews 11:6). But not only is faith essential for our salvation, faith is the key ingredient that activates every other spiritual quality that Christ has planted in us. The Christians of Galatia had lost sight of the second half of this formula. They came to Christ through faith, but afterward they got distracted by the law (vs.2-3). The law of the Jews had only ever demonstrated that human flesh is incapable of achieving perfection; therefore, Christ was needed. The Law had not worked for the Jews, why would these Gentiles (vs. 14) imagine that it might work for them? Well, false teachers had led these Galatians astray into a mode of religious legalism and futile attempts at self-righteousness.
Paul used an interesting (and perhaps not anticipatable) argument against them. He asked about how they had received the Holy Ghost and how the apostles had performed miracles among them (vs. 5). In other words, did the keeping of the law have anything to do with those demonstrations of godly spiritual power? The answer was an obvious, "No!" And Paul pointed out that Abraham had been blessed and accepted by God 430 years before the Law of Moses was even written (vs. 17).