All of you is emphatic and may mean either “all of you Gentiles” (Galatians and other non-Jewish Christians) or “all of you Galatians” (both Jews and Gentiles in the Galatian churches).

You are God’s sons carries through the metaphor of verse 25. In contrast to the minor child under the supervision of a pedagogue, God’s sons have reached the age of maturity, and therefore now enjoy the privileges and rights of mature men.

An exegetical problem in this verse is the connection between the phrases through faith and in union with Christ Jesus. Literally, this is rendered simply “through faith in Christ Jesus.” It is possible to interpret Paul as saying that “it is through faith in Christ Jesus that you are God’s sons” (Phillips “for now that you have faith in Christ you are all sons of God”; Jerusalem Bible “you … are sons of God through faith in Christ Jesus…”; New American Bible “each one of you is a son of God because of your faith in Christ Jesus”). However, most commentators interpret the verse in much the same way that Good News Translation does. It is through faith that one becomes a son of God. The expression “in Christ Jesus” should therefore be taken as an appositive to the whole statement and should be interpreted in the way that Paul uses the formula elsewhere, that is, implying close communion with Christ and in corporation into his fellowship.

Through faith is expressed in most languages as means, for example, “by means of your faith” or “… your trust in Christ.” Means, however, is expressed in some languages as cause, for example, “because you trust in Christ.” Since being God’s sons involves an actual change of state (that is, the believers were previously not God’s sons), it may be necessary to render are as “become” or “have become,” for example, “by means of your trusting Christ, you have become God’s sons.” The final appositional character of the phrase in union with Christ Jesus may then be interpreted as a kind of explanation of what has previously been said, for example, “that is to say, you are closely joined to Christ Jesus,” or “this means that you are closely joined to Christ Jesus.”

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 .