I am doing a verse by verse lesson on the book of Galatians on Wednesday evening services. Here is comments for chapter one.

Galatians was written in about 57-60 AD. The basic theme of Galatians is the end of the efficacy of grace plus nothing for salvation .

Galatians 1:[1] Paul, an apostle, (not of men, neither by man, but by Jesus Christ, and God the Father, who raised him from the dead;)
[2] And all the brethren which are with me, unto the churches of Galatia:
[3] Grace be to you and peace from God the Father, and from our Lord Jesus Christ,

Paul’s calling to Apostleship was not a personal decision nor one of men but directly by God. Called to salvation on the road to Damascus when Jesus appeared to him. (Acts 9)
Note there was more than one church at Galatia and must be separately identified independent bodies hence the need for addressing them in the plural.

[4] Who gave himself for our sins, that he might deliver us from this present evil world, according to the will of God and our Father:
[5] To whom be glory for ever and ever. Amen.

We are not here for the purpose of “changing” the world. This world is EVIL whose god is the devil (11 Corinthians 4:4) and will remain so until the cleansing of Jesus Christ from the throne in Jerusalem. Jesus did not come to change the world but to save those who believe from it. (1 Timothy 1:15)
We do not preach a gospel of progressive society but one of redemption from this evil place.

[6] I marvel that ye are so soon removed from him that called you into the grace of Christ unto another gospel:
[7] Which is not another; but there be some that trouble you, and would pervert the gospel of Christ.

The gospel of the grace of God is singular. Any other is not a “gospel” (good news) but a perversion of the true.
Among the early church there were those who taught there is no resurrection as the Sadducees. (1 Corinthians 15:12)
There were those who taught the resurrection was past. (11 Timothy 2:18)
There were those who said in order to maintain salvation you must work the works of the law. (Acts 15:5)

[8] But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed.
[9] As we said before, so say I now again, If any man preach any other gospel unto you than that ye have received, let him be accursed.

This is written about 30 years after the cross and already a different gospel other than the death burial and resurrection has cropped up. Is it any wonder that about 2,000 years later their exists so many? Any gospel other than the one presented by the Apostle Paul in the Pauline epistles in this Age is a false gospel. Based on the authority of the Word of God those preaching anything else even if it came from an angel from “Heaven” is ACCURSED. So if someone thinks it is not important what you believe as long as you are sincere need to take note: THEY ARE WRONG!
This is not just a personal opinion but solid, sound Bible New Testament doctrine.

[10] For do I now persuade men, or God? or do I seek to please men? for if I yet pleased men, I should not be the servant of Christ.

We are to persuade men and please God. Not attempting to have God see things our way but seeing things as God sees them and then convincing others. Paul would not change his message in an effort to appease false teachers or make men happy.

[11] But I certify you, brethren, that the gospel which was preached of me is not after man.
[12] For I neither received it of man, neither was I taught it, but by the revelation of Jesus Christ.

The gospel of Paul was not given to Peter, James or John but rather directly to Paul from Jesus.

[13] For ye have heard of my conversation in time past in the Jews’ religion, how that beyond measure I persecuted the church of God, and wasted it:
[14] And profited in the Jews’ religion above many my equals in mine own nation, being more exceedingly zealous of the traditions of my fathers.

Paul (Saul) had been tasked by the Jews to persecute Christians (1Timothy 1:13-15//Acts 8: 1-3 Acts 9:1-2)
He was a Pharisee (Philippians 3:5-6) before his conversion which was the most dedicated of the Jewish adherents.

[15] But when it pleased God, who separated me from my mother’s womb, and called me by his grace,
[16] To reveal his Son in me, that I might preach him among the heathen; immediately I conferred not with flesh and blood:

Paul says he was the pattern of God’s grace for the world. ( 1 Timothy 1:16)

[17] Neither went I up to Jerusalem to them which were apostles before me; but I went into Arabia, and returned again unto Damascus.
[18] Then after three years I went up to Jerusalem to see Peter, and abode with him fifteen days.
[19] But other of the apostles saw I none, save James the Lord’s brother.

This period is not covered in Acts but fell between Acts 9:19 and 9:26. NOTE in Acts 9:15 the Lord told the prophet Ananias that He was going to shew Paul great things.

[20] Now the things which I write unto you, behold, before God, I lie not.
[21] Afterwards I came into the regions of Syria and Cilicia;
[22] And was unknown by face unto the churches of Judaea which were in Christ:
[23] But they had heard only, That he which persecuted us in times past now preacheth the faith which once he destroyed.
[24] And they glorified God in me.

Acts 9:31 states the church had “rest” after the conversion of Paul.