The gift of the Spirit and His gifts are related to the acceptance of the Gospel. The Spirit has not come to them in obedience to the law but in obedience of faith. The best example to grasp this point is the story in Acts 10:1–48; (see particularly 10:44–48). The reaction of the Jewish Christians is revealing. To their surprise, God gave the Holy Spirit to the Gentiles without them obeying the Law.
The Galatians has to be really bewitched not to see the point. The Holy Spirit as the fruit of justification comes in obedience to faith. Thus, the Law is not needed.
Abraham accepted God’s promise of the offspring as numerous as the stars on the sky (Gen 15:5) with faith/trust. This trust in God’s promise was counted him as justification/righteousness. What is more, at that moment there was neither circumcision (it is only mandated two chapters later - Gen 17:10), nor the Law (it was given 400 years later - Ex 20:1–17).
The notion of the “sons of Abraham” was very dear to the Jews (John 8:39a). This identity was coming by birth - every child born of the Jewish parents or at least Jewish mother was a child of Abraham. Yet, this notion was challenged by John the Baptist (Matt 3:9), Jesus in John 8:39b–40, and now Paul. Those, who imitate Abraham’s faith/trust are the children of Abraham. Here, Paul has in mind the Gentile Christians.
The message of Gen 12:3 - “in you all the nations of the earth shall be blessed” - was preached to Abraham by God. Paul uses here the word “Gospel” as a verb. Thus, already in Genesis, Abraham was evangelized by God about the justification by faith - “that God would justify the nations by faith” (Gal 3:8), namely the same faith that Abraham showed by trusting God’s promise and obeying His word.
In Gen 12:3 and throughout the whole Old Testament, this “good news” delivered to Abraham was still a promise. In Galatians, the promise is realized. The Galatians by believing in Christ experienced that blessing promised to Abraham, and every nation that believe in Christ experiences that blessing.
Long time before the Law was given to Moses, Abraham gained his justification by his trust in God’s promise. But then, the Law was given and with the law came the curse for transgressing the law. Thus, through trust in God’s promise, one gains justification, but with the effort to obey the law comes the fear of transgression and the curse that follows the transgression. Things get even more complicated when we take the argument of Peter that the law is a burden impossible to carry = impossible to fulfill its all obligations (Acts 15:7–11).
In verses 11–12, Paul sketches two alternatives:
The contrast is clear. In the first case, the doer is God - He promises and He delivers the promise; we are only expected to trust in Him, and even this faith/trust of ours - according to Septuagint - is also God’s doing. In the second case, the doer is a person. But, he has to be careful, because if he cannot fulfill all the obligations, he falls under the curse.
Relating this idea to the situation of the Galatians. It was God who called Galatians to “the grace of Christ” (Gal 1:6). They also received the Holy Spirit “by hearing of faith” (Gal 3:2). God has already worked many miracles in their midst also “by hearing of faith” (Gal 3:5)。Why then, they want to put themselves under the law? Do they want to experience its curse?
The object of faith/trust is God; the object of the law is the fulfillment of its requirements.
Verse 13 is a climax in this argument. The verb “to redeem” is related to redeeming a slave in order to set him/her free. Thus, Paul sees those being under the law as slaves. No matter how much their struggle to ‘please their master’ - the law - there is always the fear of ‘its anger’ - the curse.
“Christ being made a curse for us” (Gal 3:13). Paul interprets Deut 21:23 as referring to Christ’s death on the Cross. Only those who were guilty of a capital offense were to be impelled on a tree and their bodies publicly exposed for others to see and be warned. Paul, however, makes it clear Christ was not guilty of a capital offense; we were (see 2 Cor 5:21 - for clear understanding). The key phrase here is “for us”. Sinless as He was Christ did not die for His own sins, but for ours and that of the whole world (1 John 2:2). The wages of sin is death (Gen 2:17). Christ himself pay this wages with his own life (see Rom 8:3).
What are the consequences of Christ’s death as “a curse for us”?
Both are gain through faith. It is interesting to notice that the promise given to Abraham was twofold: (1) the offspring and (2) the land (Gen 13:14–17). Paul here speaks about the promise of the Holy Spirit in fulfillment of God’s promise (Joel 3:1–2; see also Acts 2:33–34a).