The Mosaic law kept people under a "yoke of bondage” involving commandments, rites, sacrifices, and the sign introducing this system was circumcision, which forced people to strict obedience to the whole Law (v. 1-3).
Submission to the Law cuts us off from the blessings of the Gospel, separating us from Christ and His grace. You can not be saved by the Law and grace also (v. 4-6). See Ephesians 2:8-9.
To resort to the Mosaic Law for salvation was a step backwards for the Galatians; it did not come from Paul nor from God, but from disturbers, and was a leaven that could ruin the spiritual life of the whole Church (v. 7-9). The teacher guilty of introducing this rebellion in the church would be condemned. Paul himself was being persecuted for not insisting on the circumcision of Christians, which would undo the doctrine of salvation by the cross, so offensive to the Jews.
The Apostle wished that the false teachers would even cut themselves off! (v. 10-12).
The believer in Christ is called for "liberty", that is, he is is exempt from the observance of the Mosaic law with respect to circumcision, forbidden foods, keeping the Sabbath and feast days, sacrifices, rituals, etc. .. He is not under the Law as a code of religion.
However, this “liberty" does not allow sin - carnality, selfishness, hatred (v. 13, 15). In fact, Christian freedom leads to true spiritual life, which shows itself by mutual love, toward the Holy Spirit (v. 16, 18, and 25). This is shown in the character and conduct of the believer - not just in church meetings! It is the service for love, which is really the fulfilment of the Law (v. 14).
The Spirit and the flesh are mutually enemies; they produce conduct and character types that are opposite to each other (v. 16-18).
These are well known. Here we have mentioned here no fewer than 15 serious sins, which, along with others (v. 21), will prevent entry into the inheritance of the Kingdom of God.
Here is a great contrast - "fruit" instead of "works", "Spirit" instead of "flesh." There are nine characteristics mentioned, belonging to the Christian who walks in the Spirit, having "crucified" the flesh; they show the character and procedure of a true believer in Christ.
If we are saved through the "new birth" in the Holy Spirit, we will show new life through our walk obedient to the teachings of the Spirit; we will not be proud, wanting to show our superiority over others, thus making them envious. See James 3:18.
1 Stand fast therefore in the liberty by which Christ has made us free, and do not be entangled again with a yoke of bondage.
2 Indeed I, Paul, say to you that if you become circumcised, Christ will profit you nothing.
3 And I testify again to every man who becomes circumcised that he is a debtor to keep the whole law.
4 You have become estranged from Christ, you who attempt to be justified by law; you have fallen from grace.
5 For we through the Spirit eagerly wait for the hope of righteousness by faith.
6 For in Christ Jesus neither circumcision nor uncircumcision avails anything, but faith working through love.
7 You ran well. Who hindered you from obeying the truth?
8 This persuasion does not come from Him who calls you.
9 A little leaven leavens the whole lump.
10 I have confidence in you, in the Lord, that you will have no other mind; but he who troubles you shall bear his judgment, whoever he is.
11 And I, brethren, if I still preach circumcision, why do I still suffer persecution? Then the offense of the cross has ceased.
12 I could wish that those who trouble you would even cut themselves off!
13 For you, brethren, have been called to liberty; only do not use liberty as an opportunity for the flesh, but through love serve one another.
14 For all the law is fulfilled in one word, even in this: "YOU SHALL LOVE YOUR NEIGHBOR AS YOURSELF."
15 But if you bite and devour one another, beware lest you be consumed by one another!
16 I say then: Walk in the Spirit, and you shall not fulfill the lust of the flesh.
17 For the flesh lusts against the Spirit, and the Spirit against the flesh; and these are contrary to one another, so that you do not do the things that you wish.
18 But if you are led by the Spirit, you are not under the law.
19 Now the works of the flesh are evident, which are: adultery, fornication, uncleanness, lewdness,
20 idolatry, sorcery, hatred, contentions, jealousies, outbursts of wrath, selfish ambitions, dissensions, heresies,
21 envy, murders, drunkenness, revelries, and the like; of which I tell you beforehand, just as I also told you in time past, that those who practice such things will not inherit the kingdom of God.
22 But the fruit of the Spirit is love, joy, peace, longsuffering, kindness, goodness, faithfulness,
23 gentleness, self-control. Against such there is no law.
24 And those who are Christ's have crucified the flesh with its passions and desires.
25 If we live in the Spirit, let us also walk in the Spirit.
26 Let us not become conceited, provoking one another, envying one another.
Galatians chapter 5