The word for at the beginning of verse 26 indicates that Paul sees a direct connection between this verse and the preceding one. In the same way that a master’s son was under a pedagogue only as long as he was a minor, Paul is saying that those who come to faith in Christ are no longer minors; their relationship with the law is changed because they are now adult “sons” of God.
The term son is not, of course, exclusive to males; Paul clearly includes females in this category (Gal 3:28). The reason he uses the word sons instead of children is that he has in mind the family inheritance that was passed on to the male offspring, along with the fact that the phrase “sons of God” was the special designation of Israel in the Old Testament(Deut. 14:1, Hos. 11:1). In Christ, Gentiles now also enjoy the special relationship with God that had been exclusive to Israel.
Paul’s use of the word for in verse 27 indicates once again the close logical development of his reasoning. Paul sees baptism as a radical decision to unite our lives with Christ. InRomans 6, he describes baptism symbolically as our uniting with Jesus, both in His death and resurrection. In Galatians, Paul employs a different metaphor: baptism is the act of being clothed with Christ. Paul’s terminology is reminiscent of wonderful passages in the Old Testament that talk about being clothed with righteousness and salvation (see Isa. 61:10, Job 29:14). “Paul views baptism as the moment when Christ, like a garment, envelops the believer. Although he does not employ the term, Paul is describing the righteousness which is conferred upon believers.”—Frank J. Matera, Galatians (Collegeville, Minn.: The Liturgical Press, 1992), p. 145.
Our union with Christ symbolized through baptism means that what is true of Christ also is true of us. Because Christ is the “seed” of Abraham, as “joint-heirs with Christ” (Rom. 8:17), believers also are heirs to all the covenant promises made to Abraham and his descendants.
Dwell on this thought that what is true of Christ is also true of us. How should this amazing truth affect every aspect of our existence?