Thomas Aquinas Commentary Galatians 4:6-7

"And because ye are sons, God sent forth the Spirit of his Son into our hearts, crying, Abba, Father. So that thou art no longer a bondservant, but a son; and if a son, then an heir through God." — Galatians 4:6-7 (ASV)

Above, the Apostle revealed the gift bestowed on the Jews; here he shows that this gift also pertains to the Gentiles.

The Apostle's argument unfolds in three stages:

1. First, he mentions the gift.
2. Second, he explains the means of obtaining it (verse 6).
3. Third, he discloses the fruit of this gift (verse 7).

He says, therefore, that the gift of adoption as sons pertains not only to those who were under the Law but to the Gentiles as well. This is because you are sons of God; for not only the Jews but all who believe in the Son of God are adopted as sons: “He gave them power to be made sons of God, to them that believe in his name” (John 1:12). This gift is obtained through the sending of the Spirit of the Son of God into your hearts.

Augustine says, however, that Christ, existing in the flesh, preached primarily to the Jews, but to the Gentiles secondarily: “For I say that Christ Jesus was minister of the circumcision for the truth of God to confirm the promises made unto the fathers” (Romans 15:8). Accordingly, whatever pertains to the condition of the Jews fittingly applies to Christ.

The Galatians might have argued that they had not been adopted as sons of God, since Christ did not take on their flesh or preach to them. For this reason, the Apostle explains the manner of this adoption. He says that although they were not related to Christ physically—that is, by race or through His earthly preaching—they were nevertheless united to Him through the Spirit and were thereby adopted and made sons of God.

Hence, the conversion of the Gentiles is attributed in a special way to the Holy Spirit. Consequently, when Peter was blamed by the Jews for preaching to the Gentiles, he defended himself by appealing to the Holy Spirit, saying that he could not resist the Spirit by whose inspiration he had acted (Acts 11). And so, because God the Father sent the Spirit of His Son into our hearts—that is, the hearts of both Jews and Gentiles—we are united to Christ and are thereby adopted as sons of God.

It should be noted that while some passages of Scripture say the Holy Spirit is sent by the Father—“But the Paraclete, the Holy Spirit, whom the Father will send in my name” (John 14:26)—and others say He is sent by the Son—“But when the Paraclete cometh, whom I will send you from the Father” (John 15:26)—the Holy Spirit is nevertheless common to both the Father and the Son, proceeding from and sent by Both. Accordingly, wherever it is said that the Father sends the Holy Spirit, mention is made of the Son, as in the passage above: “Whom the Father will send in my name.” And where He is said to be sent by the Son, mention is made of the Father; hence He says, “Whom I will send to you from the Father.” Even here, when he says God the Father has sent the Holy Spirit, mention is made at once of the Son, for he adds, of his Son. Nor does it matter that the Holy Spirit is sometimes said to proceed only from the Father, for the fact that the Son also sends Him shows that the Spirit proceeds from the Son as well. Accordingly, the Holy Spirit is called the Spirit of the Son as of the One sending Him and as of the One from whom He proceeds, as well as of the One from whom the Holy Spirit has whatever He has, just as from the Father: “He shall glorify me, because He shall receive of mine” (John 16:14).

He says, into your hearts, because there are two kinds of generation. The first is carnal, which comes about through physical seed sent to the place of generation. This seed, as small as it is, contains in essence the whole person. The second is spiritual, which comes about by a spiritual seed transmitted to the place of spiritual generation—that is, the human mind or heart—because people are born as sons of God through a renewal of the mind. Furthermore, this spiritual seed is the grace of the Holy Spirit: “Whosoever is born of God sinneth not: but the generation of God preserveth him and the wicked one toucheth him not” (1 John 5:18). This seed contains, in essence, the entire perfection of beatitude; for this reason, it is called the pledge and guarantee of beatitude (Ephesians 1:14). As it is written, “I will put a new spirit within you” (Ezekiel 36:26).

This crying—that is, the Spirit making us cry out, “Abba, Father”—is not a matter of vocal volume but of a great fervor of love. For we cry, “Abba, Father,” when our affections are kindled by the warmth of the Holy Spirit to desire God: “You have not received the spirit of bondage again in fear; but you have received the spirit of adoption of sons, whereby we cry, Abba (Father)” (Romans 8:15). “Abba” in Hebrew and “Pater” in Greek both mean “father.” The author mentions both to show that the grace of the Holy Spirit is common to both peoples.

Then, with the words, Therefore, now he is not a servant, but a son, the Apostle mentions the fruit of this gift. The first fruit is the removal of all evil, as we are freed from bondage through adoption by the Holy Spirit. In this respect, he says: Therefore—that is, because the Spirit cries “Father” in us—now, in this time of grace, each one of us who believes in Christ is no longer a servant who serves in fear. As Scripture says, “I will not now call you servants but friends” (John 15:15), and, “You have not received the spirit of bondage again in fear: but you have received the spirit of adoption of sons” (Romans 8:15). Instead, we are sons: “For the Spirit himself giveth testimony to our spirit that we are the sons of God” (Romans 8:16).

Although we are still in the condition of servants (for it is said in Luke 17:10, “When you shall have done all these things that are commanded you, say: We are unprofitable servants”), we are not servants who serve unwillingly out of fear, for such a servant deserves torture and chains. Rather, we are good and faithful servants who serve out of love. For this reason, we obtain freedom through the Son: “If, therefore, the son shall make you free, you shall be free indeed” (John 8:36).

Second, he mentions the fruit as it pertains to attaining every good. In this regard he says: And, if a son, an heir also through God. As it is written, “And if sons, heirs also: heirs indeed of God and joint heirs with Christ” (Romans 8:17). Now this inheritance is the fullness of all good, for it is nothing other than God Himself, according to the Psalm: “The Lord is the portion of my inheritance” (Psalms 15:5). He said to Abraham: “I am thy reward exceeding great” (Genesis 15:1). He says, through God, because just as the Jews obtained the inheritance through God's promise and justice, so the Gentiles too received it through God—that is, through the mercy of God: “But the Gentiles are to glorify God for his mercy” (Romans 15:9). Or, it is through God because it is through the working of God: “Thou hast wrought all our works for us, O Lord” (Isaiah 26:12).