In this verse Paul uses the second person singular pronoun, thus zeroing in, so to speak, on each individual reader.

So then connects this verse not only with verse 6, but with everything from verses 1 to 6. The gift of the Spirit, referred to in verse 6, confirms the gift of sonship. In some languages it may be useful to translate so then as “because of what God has done,” or “as a result of what has happened.” In other languages one may employ an adverbial connective such as “therefore.”

The clause you are no longer a slave implies at least two things: (1) Sonship includes freedom from bondage; one who has been made a son of God is no longer under the bondage of the Jewish Law or of any other force in the world. (2) Paul’s use of no longer makes it clear that his readers were formerly under bondage. You are no longer a slave must refer to the bondage of persons to the elemental spirits of the universe or to the Law. Since this is a direct reference to the Galatians, it may be useful to translate “you are no longer in bondage to the spirits that rule the universe,” or “you no longer have to serve those spirits.” Similarly the phrase but a son must often be expanded to indicate whose son, for example, “but you are a son of God.”

And since you are his son, God will give you all that he has for his sons is literally “and if a son, also an heir through God.” The use of the word “heir” reminds one of Roman law, where all the children, whether sons or daughters, natural or adopted, inherited alike. Paul reminds his readers that each one of them, as a son, enjoys the full privileges of sonship and will receive from God everything that he promised to Abraham. The addition of the expression “through God” reminds Paul’s readers of two things: (1) their sonship is a gift from God alone and not through any effort or merit on their part; and (2) since it is all from God, then God will certainly see to it that whatever he has promised to his sons will be realized.

Quoted with permission from Arichea, Daniel C. and Nida, Eugene A. A Handbook on Paul’s Letter to the Galatians. (UBS Handbook Series). New York: UBS, 1976. For this and other handbooks for translators see here .