Appeal to the personal experience of the Galatians.
3:1 You foolish [Phillips translation: “My dear idiots. . .” (although word “idiot” is not in the text)] Galatians! Who has bewitched [cast a spell] you [Paul amazed at senseless choice Galatians were making in abandoning the gospel of grace for a message that would put them back under bondage]? [notice facts concerning his preaching] Before your very eyes Jesus Christ was clearly [publicly] portrayed [same word used for posting public notices in the marketplace] as crucified [content of Paul’s message emphasized Christ’s crucifixion, a past event with present results].
Note: This verse communicates Paul’s frustration and compassion. The Galatians had heard a clear presentation of the gospel message and apparently understood it. They had no excuse for polluting that message of salvation with teachings about the necessity of rites, rituals, or ceremonies.
3:2 [Paul asked five rhetorical questions to emphasize that every benefit the Galatians had received from God came from grace, not legalism] I would like to learn just one thing from you:  Did you receive the Spirit by observing the law, or by believing what you heard?
Note: The answer to the question in verse 2 was no. The Galatians had trusted Christ for their salvation and then immediately received the Holy Spirit. Paul hoped that his questions would cause the Galatians to think long and hard about how they were saved and then cause them to reaffirm their commitment to Christ and the gospel of grace.
3:3  Are you so foolish?  After beginning with the Spirit [cf. Phil 1:6], are you now trying to attain your goal by human effort [cf. Col. 2:6]?
Note: Phillips translation: “Surely you can’t be so idiotic as to think a person begins a spiritual life in the Spirit and then completes it by reverting to outward observances.”
3:4  Have you suffered so much for nothing [Galatians had experienced persecution because of their faith in Christ] — if it really was for nothing [to turn away from Christ would mean they suffered in vain]?
3:5  Does God give you his Spirit and work miracles among you because you observe the law, or because you believe what you heard?
Note: Paul asked whether the miraculous transformation of their lives was caused by grace or by the law.
3:6 Consider Abraham [the first of the OT patriarchs; founder of the Jewish nation]: “He believed God [concerning the promise of an heir], and it was credited to him as righteousness [Abraham was declared righteous fourteen years before he was circumcised (cf. Rom. 4:10-12)]. [cf. Gen. 15:6]”
3:7 Understand, then, that those who believe are children [descendants] of Abraham.
3:8 The Scripture foresaw [indicates that salvation by faith (for Jews and Gentiles) was God’s plan from the beginning] that God would justify the Gentiles by faith, and announced the gospel in advance to Abraham: “All nations [not just the Jews] will be blessed through you [because Abraham’s descendant, Jesus Christ, would bring salvation to all who believe]. [cf. Gen. 12:3; 22:18; God made this promise to Abraham before the law was given]”
3:9 So [for this reason] those [only the individuals in the “all nations” of Gal. 3:8 who believe] who have faith are blessed along with Abraham, the man of faith [cf. Heb. 11:8-19].
Argument regarding man’s inability to obey the law.
3:10 All who rely on observing the law are under a curse, for it is written [Paul appealed to the Scripture to support his case that God gives righteousness by faith]: “Cursed is everyone who does not continue to do everything written in the Book of the Law [Deuteronomy 27:6: teaches that a person must keep all the law, not just some of the law, or come under divine condemnation; cf. James 2:10].“
Note: Paul’s point in verses 10-14: Anyone seeking to earn God’s favor by observing the law has no hope of salvation.
3:11 Clearly no [illustrates inability to earn righteousness by obedience] one is justified before God by the law, because, “The righteous will live by faith [Habakkuk 2:4: illustrates that faith, not works, brings life and salvation.].”
3:12 The law [law demanded deeds] is not based on faith [gospel demanded faith in Christ]; on the contrary, “The man [those who choose to live under the law must obey all the law] who does these things will live by them [Leviticus 18:5].”
3:13 Christ redeemed [originally referred to payment for purchase of a slave] us from the curse of the law by becoming a curse [substitutionary] for us [Christ took our place — became “a curse for us” — thus setting us free from the judgment we deserve], for it is written: “Cursed is everyone who is hung on a tree [Deuteronomy 21:23: shows that death of Christ on cross redeems us from curse of the law].”
Note: Paul used the word “redeemed” to illustrate that through the death of Christ we are purchased from the penalty and bondage of our sin — the death of Christ cancelled the penalty of the law applied to our lives. The reference to hanging on a tree referred to the practice of hanging the dead body of a condemned criminal on a tree as a means of public humiliation.
3:14 He redeemed us in order that the blessing given to Abraham [the salvation Abraham experienced because of his faith in God is available to all who place their trust in Jesus Christ; cf. Gal. 3:6-9,15-22] might come to the Gentiles through Christ Jesus, so that by faith we might receive the promise of the Spirit.
3:15 Brothers [a reminder that even Christians who disagree can relate courteously to one another], let me take an example from everyday life. Just as no one can set aside or add to a human covenant [will, agreement, contract] that has been duly established [a legal agreement made between two parties cannot be changed by third party], so it is in this case [God promised righteousness by faith to Abraham, no one can alter the terms of this contract].
Note: Paul anticipated the argument that the giving of the law in the time of Moses replaced the giving of the promise to Abraham. Paul dealt with this argument in verses 15-18. In verse 15 Paul illustrated the enduring nature of the promise given to Abraham by using an analogy from human custom: When a legal agreement is made between two parties it cannot be changed by a third party.
For example, in real estate, when a buyer and seller agree in writing on the price of a house, no third party can alter the agreement. When God promised righteousness by faith to Abraham, no one else can alter the terms of that agreement. The original agreement that righteousness comes by faith (Genesis 15:6) stands.
Paraphrase of the thought in verses 15-18: God made an unconditional agreement with Abraham that He would bless him and all those who shared Abraham’s faith. The Mosaic law that came 430 years after this agreement could not invalidate the original promise God made.
3:16 The promises were spoken to Abraham and to his seed [Jesus; however, benefits of the promise made to Abraham extended also to Abraham’s offspring/posterity or those who trust Jesus for salvation]. The Scripture does not say “and to seeds,” meaning many people, but “and to your seed,” meaning one person, who is Christ [those spiritually related to Abraham through their faith in Jesus Christ will share in the blessings that God promised to Abraham and become the sons of Abraham].
3:17 What I mean is this: The law [Ten Commandments], introduced 430 years [the time between God’s promise to Abraham and the receiving of the law by God’s people] later, does not set aside [giving of the law did not replace the promise; God did not intend for the law to alter the method of coming to Him by faith as Abraham did] the covenant previously [with Abraham] established by God and thus do away with the promise [God did not give a promise only to later change it to make it conditional on keeping the law].
3:18 For if the inheritance [God’s blessings] depends on the law, then it no longer depends on a promise [law and grace are like oil and water — they don’t mix; you cannot obtain God’s promise by faith and works]; but God in his grace gave [permanently] it to Abraham through a promise [God’s original promise to Abraham was based on faith, not works].
3:19 What, then, was the purpose of the law? It was added because of transgressions [like a mirror, the law could reveal transgressions but it could not prevent or erase them] until [stressed temporary and preparatory nature of the law; Jesus fulfilled the promise and the law] the Seed [Jesus] to whom the promise referred had come. The law was put into effect through angels by a mediator.
Note: The phrase “put into effect by a mediator” … “may mean that God sent angels to reveal the law to Moses rather than speaking directly to Moses.” (Galatians: Saved by Grace • by Thomas D. Lea • p. 56)
3:20 A mediator [a middle person between two parties; Moses], however, does not represent just one party; but God [who made the promise to Abraham] is one [no mediator required when promise made to Abraham; implication: law inferior to the promise].
3:21 Is the law, therefore, opposed to the promises of God? Absolutely not! For if [in reality not possible for law to provide salvation] a law had been given that could impart life, then righteousness would certainly have come by the law.
3:22 But the Scripture [OT] declares that the whole world is a prisoner [one with no way of escape] of sin, so that what was promised [Abraham’s faith was in One yet to come], being given through faith in Jesus Christ, might be given to those who believe [Galatians trusted One who had already come].
Purpose of the law revealed.
3:23 Before this faith came, we were held prisoners [pictures someone being locked in a room with no way of escape — the law shows people how desperate their condition really is] by the law, locked up until faith [only way of release] should be revealed.
3:24 So the law was put in charge [guardian: a function of the law; like a Greek guardian (tutor or pedagogue) in charge of a child, the law served in this capacity only for a limited time] to lead [readying those under law to accept gospel of justification by faith] us to Christ that we might be justified by faith.
Note: Tutor: custodian hired and charged with the responsibility of attending to and disciplining Greek and Roman youngsters. Tutor watched over child’s behavior, escorted child to and from school, administered discipline. Youngsters looked forward to the day when they would be free from the supervision of a tutor.
Note: “…the law functions like a checkmate in a chess game. It blocks off all routes for escape from God’s verdict and opens the sinner to God’s solution through Christ.” (Galatians: Saved by Grace • by Thomas D. Lea • p. 58)
3:25 Now that faith has come [with Christ’s coming there was no longer a need for a tutor like the rituals of the Old Testament designed to show us our sinfulness and guide us to Christ], we [those who have placed their faith in Christ] are no longer [law no longer functioned as a tutor; no need to obey Jewish rites/rituals to receive salvation] under the supervision of the law.
3:26 You are all [promise of sonship applies to Jews/Gentiles; no second-class citizens in God’s kingdom] sons of God through faith in Christ Jesus,
3:27 for all of you who were baptized [baptism was means by which believers confessed new relationship to Christ; does not bring about the relationship, only represents the public expression/statement of that relationship] into Christ have clothed [metaphor of being clothed describes a believer’s union with Christ] yourselves with Christ.
Note: When the Galatians put their faith in Christ they laid aside the old garments of the law and put on the garments of Christ’s righteousness.
3:28 There is neither [a statement of fact; all believers equal before God; Paul listed categories that have been transcended in Christ] Jew [circumcised; Jewish male thanked God that he was not a Gentile, a slave, or a woman] nor Greek [uncircumcised], slave [had no rights] nor free [had many rights], male nor female, for you are all one in Christ Jesus.
Note: This does not mean that there are not differing roles and functions between sexes or employers and employees.
3:29 If you [Gentiles included] belong to Christ [those in Christ become heirs to God’s promises to Abraham and his “seed” which is Christ Jesus], then you are Abraham’s seed [a true Jew], and heirs according to the promise.