New Defender's Study Bible Notes
3:22 all under sin. The law “was added because of transgressions” (Galatians 3:19), to make it clear what sin is—as a transgression of the character and will of God. When people understand the nature of sin, it soon becomes clear that all are sinners (Romans 3:10,12,23) and need to come to Christ for forgiveness and salvation.
3:24 schoolmaster. A “schoolmaster” (Greek paidagogos) was a person (often a slave) who was delegated as tutor and guardian for young boys until they came of age (usually about eighteen years of age). It was a temporary, and not very prestigious, position. When the son entered on all the privileges of adult sonship, the schoolmaster’s responsibilities were finished. Paul compares this domestic relationship to the spiritual relationships when Christ replaces the law as the controlling basis of our lives.
3:27 baptized into Christ. See Romans 6:3; I Corinthians 12:13. When we have been “immersed” into the spiritual body of Christ, then He becomes our spiritual identity.
3:28 all one in Christ. Although national identity, economic status, marital relationship and other such distinctions are very real in the divine economy, our position in Christ is completely independent of any such matters. Every Christian is saved simply through faith in Christ and will be rewarded as a Christian simply in relation to what he or she has done in proportion to light and opportunities given, as well as their motives in doing it (I Corinthians 3:11-15).