[Galatians has a very significant place in the New Testament. It is a foundational source for the theologies of Augustine and Luther. However, we are reminded that the arch-heretic Marcion placed it first in his canon. The reader's perspective matters.]
Galatians is written to churches in an area which is modern day Turkey. The people were descendents (circa 275BC) of Celtic invaders who came under Roman dominion around 25BC. They maintained their own language and customs. Paul visited this area three times and the letter is thought to have been written between 48 and 54AD.
The letter clearly begins with Paul is establishing his credentials as a legitimate apostle ("not from men, or a man but Jesus Christ and God the Father"). One of the realities of church life is conflict. From the beginning there have been disagreements. Sin is in the church. This is why the words "to rescue us from the present evil age" are so vital. The salvation in Jesus is a rescue operation. The age (every age) is evil. There was no golden time of pure faith. There has always and only been an evil age from which we need rescuing.
Paul had been there, and later some other missionaries had come amongst the Galatians and made alterations of what they had heard. These men said that Gentile Christians should adopt Jewish practices associated with circumcision and Torah. The missionaries are no doubt Jewish Christians (all of the first Christians were), but this group tried to conserve that Jewish identity and practice. They may well have been Pharisees who had become Jesus-believers. Now these men are afraid something vital is lost by Paul's interpretation of the Christian Way. Conservatives remind us that we must move slowly and not lose what is essential. In this case, the men were advocating non-essentials. Paul condemns (anathema in Greek) them most strongly. Whatever their sincerity and motivations, they were proclaiming a deadly lie.
I have some feelings of compassion for these "other" preachers. Paul's insights were driven by his experiences with God--he calls it a revelation (1:12). His insight into the meaning of Jesus far surpassed most in the church. Yet, I also understand Paul's passionate concern. He was seeing his church led astray by men who would replace Jesus with an inadequate alternative. These men had also, it seems, called into question his status and motivation (he is a late comer who did not know Jesus and is trying to make it easy on Gentiles to please them).
Paul responds to the criticism by providing some biography. 'I used to persecute the church but now I do not,' he says, 'and I did not learn what I know from anyone.' He spent fourteen years sharing what Jesus revealed to him with the Gentiles. For Paul, the point is what God had done in Jesus: created one family of God's children. It was about being God's children (not Jews or Gentiles), united in the Messiah King Jesus. Jesus is our representative who makes us right with God. He alone is the one in whom all people find hope.
It is like a man who is able to walk on a tight rope (thanks to NT Wright for this analogy). We sit on his back. If we decide to get off half way across, well..... splat! Returning to Torah observance is futile, because, as Paul demonstrates in chapter 3, the Torah cannot accomplish that. Our identity as God's people is based on relationship with Him in Jesus. The Torah served its purpose, it was a "baby sitter" until the Lord arrived, but now that Jesus is here Torah is filled up in Him. The Torah is limited, it can only tell us what to do. The Torah curses anyone who breaks even one law---which we all do. So we are cursed. The only hope is Righteous One who takes our curse on (which Jesus does on the cross) Himself and frees us.
Applying this teaching to our own age, which is also an age of evil, is vital. However, we need to look first at how "I am missing the point" rather than assuming "I got it right and Paul is talking about them!" In the end, the sad reality is Paul says God wants one family. One people. One; and we are growing more divided and individualized each day. So, we are all under judgment right now, and the sorry state of the church may be the wrath (or curse) of which Paul is warning us. We have hope for ultimate rescue, but right now, we are in the thick of the mess and we, and the world, are the worse for it.