Now that Paul has established his authority, he proceeds to his message. He provides seven lines of argument against the Judaizers, who taught that good works are necessary as a way of salvation. For the next six weekdays, we will consider these arguments.
Paul's first argument (3:1–2) is that the Galatians had been justified by faith and received the Spirit by faith. He asked them this: Did you receive the Spirit by earning it through good works, or did you receive the Spirit by simply believing the Gospel and putting faith in God? We might call this "the argument from Pentecost," because it builds on the fact that the Spirit was not poured out under the old covenant. Keeping the law did not earn the Spirit in the old covenant; rather, the Spirit came when Christ had completed His work. Thus, by pushing the church back under the old covenant, the Judaizers were working to get rid of the Spirit.
In the same way, the Galatian believers had received the Spirit when they believed. Many of them had been old covenant believers, either faithful Jews or God-fearing Gentiles, but only when they heard the Gospel did they receive the Spirit. Paul asked them to recall their experience. Did they enter into the pentecostal new covenant age by keeping the law or by believing the Gospel?
Paul's second argument (3:3–5) is that the Galatians could only be sanctified by faith. Paul asked them to explain their reasoning, having begun in the Spirit, they hoped to grow in the faith by going back under the law. How could this make any sense? asked Paul. Actually, he said, it is "brainless" (v. 3).
Sanctification involves both our own faithful efforts and the empowering of the Spirit, but the Galatians apparently believed that faith is not a daily affair but a one-time decision. They exercised faith once and now were going to live the "Christian life" by means of human effort alone. Paul told them just how foolish this thinking is. He exhorted them to live the Christian life by means of daily faith and moment—by—moment trust in the Holy Spirit. They were to recognize that all of their good works were done in the power of the Spirit, and thus had no merit of their own.
The wonderful blessings that come with new life in the Spirit are not earned. They are God's gifts to enable us to live the Christian life. When we act as if we have to earn them, we are actually rejecting them because gifts by definition are not earned. Thank God for the gifts He gives you to give back to Him.