v1-9 - In the first two chapters, Paul cements his credentials as an apostle who has God given authority over the church. Today, he gets to the point of this letter without mincing any words. He begins by calling them mindless (translated 'foolish' in the NIV), because they're not thinking. Christianity is not a religion of rote ceremonies and rituals, or even just warm fuzzy feelings. Christianity is a declaration that you've been made right with God because of the blood of Christ, and the only requirement is that you apply that knowledge to every aspect of life. In other words, Paul is pleading with the Galatians (and you) to think clearly. Here's a synopsis of this passage:
You received the Spirit
by believing what you heard,
not by performing religious rituals.
Since the Spirit has begun this work in you,
don't try and finish it yourself;
in other words, don't bend Christianity into something it isn't.
After all, Abraham
simply believed God
and this belief was credited to him as righteousness.
v10-14 - Remember, the key issue in this letter is that the Galatians had been influenced by Jewish Christians that although it was grace that brought them into salvation, it was religious works (circumcision, washing rituals, observing religious feasts, etc.) that kept them in their salvation. Paul writes this letter to remind us that we are saved by faith alone, and that we persevere in our salvation by faith alone.
v15-25 - This passage explains that the law was a good thing. Understand that in this context, the 'law' is more than just God's commandments, but that it refers to all of the Jewish religious ceremonies and requirements found in the first five books of the Bible (the Pentateuch). Paul calls the law a 'guardian' which preserved God's people until Christ came (v24). "The Law was humanity’s paidagōgos (“pedagogue”). A paidagōgos was a household slave wh