The churches of Galatia (Antioch of Pisidia, Iconium, Lystra and Derbe) were founded by Paul himself (Acts 16:6; Gal 1:8; 4:13, 4:19). They seem to have been composed mainly of converts from paganism (4:8). After Paul's departure, the churches were led astray from Paul's Christ centered teachings by individuals proposing "another gospel" (which centered around Judaism and salvation through the Mosaic Law, so-called Legalism (theology)), whom Paul saw as preaching a "different gospel" than that of Jesus Christ (which was centered around salvation by God's grace and Christ's atonement, not the "works" of the Mosiac law). (1:6–9). The Galatians appear to have been receptive to the teaching of these newcomers, and the epistle is Paul's angry response to what he sees as their willingness to turn from his teaching.
The identity of these "opponents" is disputed. We do not have a record of their activity, but are left to reconstruct it from Paul's response. However, the majority of modern scholars view them as Jewish Christians (i.e. Judaizers), who taught that in order for pagans to belong to the people of God, they must be subject to some or all of the Jewish Law. The letter indicates controversy concerning circumcision, Sabbath observance, and the Mosaic Covenant. It would appear, from Paul's response, that they cited the example of Abraham, who was circumcised as a mark of receiving the covenant blessings see also Abrahamic religion. They certainly appear to have questioned Paul's authority as an apostle, perhaps appealing to the greater authority of the Jerusalem church governed by James the Just.
Paul responds angrily; he relates his conversion and apostolic credentials, his relationship with the Jerusalem Church, and engages in a debate over the interpretation of the Abraham story.
Virtually all scholars agree that Galatians is one of the most certain examples of Paul's writing.
The main arguments in favor of the authenticity of Galatians include its style and themes, which are common to the core letters of the Pauline corpus, and the historical connection to Acts of the Apostles. Moreover, Paul's description of the Council of Jerusalem (Gal 2:1–10) gives a different point of view from the description in Acts 15:2–29, whereas a forger writing in later decades would most likely have stuck close to the account in Acts to convince his audience that this was an authentic writing by Paul.
The central dispute in the letter concerns the question of how Gentiles could convert to Christianity, which shows that this letter was written at a very early stage in church history, when the vast majority of Christians were Jewish or Jewish proselytes. This puts it during the lifetime of Paul himself.
There is no hint in the letter of a developed organization within the Christian community at large.
There are three main theories about when Galatians was written and to whom. The North Galatian view holds that the epistle was written very soon after Paul's second visit to Galatia (Acts 18:23). The visit to Jerusalem, mentioned in Gal 2:1–10, seems identical with that of Acts 15, or possibly Acts 18:22 (at the end of his Second Missionary Journey), and it is spoken of as a thing of the past. Consequently, the epistle seems to have been written after the Council of Jerusalem. The similarity between this epistle and that to the Romans has led to the conclusion that they were both written at the same time, namely, in the winter of AD 57–58, during Paul's stay in Corinth (Acts 20:2–3). This letter to the Galatians is written on the urgency of the occasion, tidings having reached him of the state of matters; and that to the Romans in a more deliberate and systematic way, in exposition of the same fundamental doctrines of the gospel.
The South Galatian view holds that Paul wrote Galatians before or shortly after the First Jerusalem Council, probably on his way to it, and that it was written to churches he had presumably planted during either his time in Tarsus (he would have traveled a short distance, since Tarsus is in Cilicia) after his first visit to Jerusalem as a Christian (Acts 9:30), or during his first missionary journey, when he traveled throughout southern Galatia.
A third theory is that Galatians 2:1-10 is the visit of Acts 11:30. This theory implies that the epistle was written before the Council was convened, making it the earliest of Paul's epistles.
In Chapter 1 he defends his apostolic authority (1:11–19; 2:1–14). Chapters 2, 3, and 4 show the influence of the Judaizers in destroying the very essence of the gospel. Chapter 3 exhorts the Galatian believers to stand fast in the faith as it is in Jesus, and to abound in the fruit of the Spirit. Chapter 4 then concludes with a summary of the topics discussed and with the benediction, followed by 5; 6:1–10 teaching about the right use of their Christian freedom. For example, it is clear that some took "freedom in Christ" as justification of antinomianism.
In the conclusion of the epistle (6:11), Paul writes, "Ye see how large a letter I have written with mine own hand." It is implied that this was different from his ordinary usage, which was simply to write the concluding salutation with his own hand, indicating that the rest of the epistle was written by another hand. Regarding this conclusion, Lightfoot, in his Commentary on the epistle, says: "At this point the apostle takes the pen from his amanuensis, and the concluding paragraph is written with his own hand. From the time when letters began to be forged in his name (2 Thess 2:2; 3:17) it seems to have been his practice to close with a few words in his own handwriting, as a precaution against such forgeries... In the present case he writes a whole paragraph, summing up the main lessons of the epistle in terse, eager, disjointed sentences. He writes it, too, in large, bold characters (Gr. pelikois grammasin), that his hand-writing may reflect the energy and determination of his soul."
An interesting literary interpretation of this period of Christianity and the character of Paul can be found in Rudyard Kipling's short story "The Church that was at Antioch". A Roman soldier and follower of Mithraism discovers the faith on his death bed, after having tried to defuse tension between the Gentile and Jewish Christians over issues of Mosaic Law such as circumcision and the preparation of food.