Galatians 5: the free beggar

The beggar can´t survive by himself. The Christian is the beggar who is aware that he can't trust in his own works to get near the Lord. The Christian knows that he can only trust in the cross - Jesus died to him and that's why the Lord accepts him. When the beggar is aware of his condition, and aware of what he has received, he is free of himself. He is free for loving others. The Spirit moves in him producing love, peace, joy, patience; but when he trusts in his own works (ex: circumcision), he begins to exalt above others. Instead of loving, he competes with others trying to be some imaginary race. He hates others. He wants to be the number 1.
Am I aware of my condition? 

Galatians 4: The Creator is the "Papa/Father" to those who has Jesus.

 Paul said to the Galatians:
4-7 But when the time arrived that was set by God the Father, God sent his Son, born among us of a woman, born under the conditions of the law so that he might redeem those of us who have been kidnapped by the law. Thus we have been set free to experience our rightful heritage. You can tell for sure that you are now fully adopted as his own children because God sent the Spirit of his Son into our lives crying out, “Papa! Father!” Doesn’t that privilege of intimate conversation with God make it plain that you are not a slave, but a child? And if you are a child, you’re also an heir, with complete access to the inheritance.

Paul said that the Galatians were kidnapped by the Law, but Jesus came to redeem them; so they don't have to (or must not to) apply the ceremonial law (make the circumcision) to them. They became children of the Lord, and they now have the Spirit of Jesus into their lives crying "Papa!" to the Lord.
Paul remembers how the Galatians were friendly to him, but now, due to the Judaizers, he feels that their relations is colder. He said that the Judaizers want them to become slaves when in fact they were the slaves (of the Law).

Galatians 3: Who are the people of the Lord? trust vs ceremonial law

The Galatians believed in Jesus. There were signs that the Spirit was with them; however, they received Christian-Jews who told them that the ceremonial law, the circumcision, was necessary to be seen as the people of Lord. Why did they listen to these Christian-Jews? Because they were descendants of Abraham, because they were the people that received Moses and the prophets. Paul used the Old Testament to argument that the Galatians are in fact the people of the Lord not by the law but by trusting in Jesus because:
Genesis 15:6 - Abraham was saved (seen as just by the Lord) by faith before the Law.
Genesis 12:3 - The promise to Abraham included all nations.
Deuteronomy 27:26 - The Law demands perfection (and we fail).
Habakkuk 2:4 - The righteous live by trusting God.

Therefore, the Galatians don't need to be circumcised to be accepted by the Lord. In fact, they were already accepted by the Lord when they trusted in Jesus, and it was notorious that the Spirit was with them.

5-6 Answer this question: Does the God who lavishly provides you with his own presence, his Holy Spirit, working things in your lives you could never do for yourselves, does he do these things because of your strenuous moral striving or because you trust him to do them in you? Don’t these things happen among you just as they happened with Abraham? He believed God, and that act of belief was turned into a life that was right with God.

Galatians 2: The beauty of the cross

Paul says that he has authority given by Jesus. He was not ordained by anyone. Thus, when he says that salvation comes from Jesus, and Jesus only; he is claiming that he has authority to say so. He also says that no one can be saved by keeping the law and the Jews know it very well because they are unable to keep all the law. Besides, when someone says that although Jesus saves, it is still necessary to keep the law for salvation, he is not seeing the beauty of the cross, he is not seeing the beauty of the Jesus' sacrifice.
By the cross, Jews and gentiles can live together, in harmony.
By the cross, we are free to be ourselves before the Lord; we don't need masks because we are accepted by Jesus and not by what we do.
Paul rebuked Peter when he disguised that he behaved more like a Jew in front of the Jews and gentiles. For Paul, Peter was in fact distorting the gospel, he was an hypocrite because he knew that Jews and gentiles could live in harmony by the cross. Peter's behavior would send a message that circumcision is important and causes division. 

Paul says:

19-21 What actually took place is this: I tried keeping rules and working my head off to please God, and it didn’t work. So I quit being a “law man” so that I could be God’s man. Christ’s life showed me how, and enabled me to do it. I identified myself completely with him. Indeed, I have been crucified with Christ. My ego is no longer central. It is no longer important that I appear righteous before you or have your good opinion, and I am no longer driven to impress God. Christ lives in me. The life you see me living is not “mine,” but it is lived by faith in the Son of God, who loved me and gave himself for me. I am not going to go back on that.

Galatians 1: Another gospel

Paul writes to the Galatians. Perhaps, this is the first letter of Paul written around 48AD or perhaps it comes after the letters to the Thessalonians, in this case, it was written around 54AD. In this letter, Paul is furious because others has added some words to the gospel from: "salvation comes from Jesus" to another gospel: "salvation comes from Jesus and circumcision".  
Let us say that it was the very first letter of Paul. In this case, it was written to the people of Pisidian Antioch, Iconium, Lystra, and Derbe before the council of Jerusalem in Acts 15 where it was stated that circumcision was not necessary for salvation, for the believers. In the letter to the Galatians there is no reference to the Council of Jerusalem so it seems that this was an open question in the beginning of Christianity.
Paul writes:

6-9 I can’t believe how you waver—how easily you have turned traitor to him who called you by the grace of Christ by embracing an alternative message! It is not a minor variation, you know; it is completely other, an alien message, a no-message, a lie about God. Those who are provoking this agitation among you are turning the Message of Christ on its head. Let me be blunt: If one of us—even if an angel from heaven!—were to preach something other than what we preached originally, let him be cursed. I said it once; I’ll say it again: If anyone, regardless of reputation or credentials, preaches something other than what you received originally, let him be cursed.

However, who is about to be cursed? People who says that believe in Jesus because they were in the church. Paul is very clear that salvation comes from Jesus and it is really a great gift from the Lord.

If Galatians is really the first letter of Paul, then Paul states from the beginning of his career how important is the sacrifice of Jesus.

2 Thessalonians 3: taktos, in order

Some people in Thessalonian church stopped working. Perhaps they were waiting Jesus return. A soldier must be taktos, in his position, in order. Paul uses this military term to command the lazy people that as soldiers, they must come back to their position so that they defend themselves together. When someone stops working, he leaves the church more vulnerable. Paul says how to deal with them: to ostracize them in order that they repent and come back to their ranks.
Paul writes:

6-9 Our orders—backed up by the Master, Jesus—are to refuse to have anything to do with those among you who are lazy and refuse to work the way we taught you. Don’t permit them to freeload on the rest. We showed you how to pull your weight when we were with you, so get on with it. We didn’t sit around on our hands expecting others to take care of us. In fact, we worked our fingers to the bone, up half the night moonlighting so you wouldn’t be burdened with taking care of us. And it wasn’t because we didn’t have a right to your support; we did. We simply wanted to provide an example of diligence, hoping it would prove contagious.

2 Thessalonians 2: What to expect before Jesus returns?

The Thessalonians received a false letter of Paul saying that Jesus had already returned. They were facing troubles due to their faith, but if Jesus had already returned so, were everything in vain? were they abandoned by the Messiah? Paul wrote:

1-3 Now, friends, read these next words carefully. Slow down and don’t go jumping to conclusions regarding the day when our Master, Jesus Christ, will come back and we assemble to welcome him. Don’t let anyone shake you up or get you excited over some breathless report or rumored letter from me that the day of the Master’s arrival has come and gone. Don’t fall for any line like that.

Paul wrote that Jesus hadn't return and there will be signs before it happens:

- the apostasy 

- the man of Lawlessness - one man that sits in the temple of God (in Jerusalem?) proclaiming to be God.

Paul said that there is a Restrainer - one that is restraining the power of the Lawlessness.
Paul said:

13 But we should always give thanks to God for you, brothers and sisters beloved by the Lord, because God has chosen you from the beginning for salvation through sanctification by the Spirit and faith in the truth. 14 It was for this He called you through our gospel, that you may obtain the glory of our Lord Jesus Christ. 15 So then, brothers and sisters, stand firm and hold on to the traditions which you were taught, whether by word of mouth or by letter from us.

According to Paul, I (or a Thessalonian) was chosen for salvation through sanctification by the Spirit and faith in the Truth, so that I may obtain the glory of our Lord Jesus Christ. May the Spirit work on me; may I grow in the Truth; may I obtain the glory of Jesus (be resurrected).