In this verse Paul reminds the Galatians of their former state, to prepare them for the warning he is about to give regarding the folly of their proposed actions.
In the Greek the verse starts with “but then,” and while most translations omit the connective, it is possible to interpret it to mean that Paul’s description of the former state of the Galatians and of their apostasy is in direct contrast to their description as children of God in the previous section.
In the past may be expressed in some languages as “in former days,” but past time may be characterized specifically in terms of having occurred prior to faith in Jesus Christ, and therefore one may translate “before you believed in Jesus.”
The verb form of you did not know is a perfect (but used as a present) tense to refer to a period of time simultaneous with the main verb (you were slaves) and thus in the past (Good News Translation in the past; New English Bible and others “formerly”). Most interpreters take the position that, since Paul says that in their former state the Galatians were ignorant of God, he had in mind primarily the non-Jews among them, for the Jews would have had a knowledge of God before they became Christians. It is possible, however, to understand the Jews’ subservience to the Law as a form of ignorance of God. In fact, the phrase know God must be understood in this context (as well as in many other contexts in Paul’s letters) as indicating intimate relationship with God. It is far more than merely “knowing about God.” An equivalent expression in some languages may be “you really were not personally acquainted with God,” or “you had never met with God.”
And so implies the reason for Paul’s mentioning the matter of their ignorance of God. Since they were ignorant of God, one could understand why they were in a state of slavery. It is interesting to note that the word translated you were slaves is related to the word Paul uses when he talks of being a “servant” of Jesus Christ. In Christ, of course, this relationship is characterized by freedom, not bondage.
The expression beings who are not gods is literally “the ones which by nature are not gods.” The word for “nature” refers to one’s essential character. While Paul does not deny that these beings are called “gods,” he does deny that they are deities. In other words, they are “gods who are really no gods at all” (Moffatt).
The main difficulty here is to determine what Paul was referring to by this description. Was he referring to the idols which the Galatians formerly served, to the “elements of the world” referred to in verse 3, or to the pagan deities which in another letter he refers to as “demons”? (1 Cor 10.20). Or did he include in this description the Jewish Law which had taken the place of God in Jewish life? It is not easy to choose an answer, but in view of the nature of Paul’s readers, an interpretation that would include both Jews and Greeks would be preferred. The only equivalent of beings who are not gods in some languages is “spirits who are not gods.” This would be a reference to those spirits in the universe which indwell nature but which are not regarded as having supernatural power over certain domains of nature. If, however, one endeavors to include the Jewish Law in beings who are not gods, then it may be necessary to use some relatively impersonal expression such as “powers which are really not gods.” Such a generic expression as “powers” is, however, relatively rare in receptor languages, and therefore one may be forced to settle for an expression such as “spirits.”
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 .