26 For you are all sons of God through faith in Christ Jesus.
27 For as many of you as were baptized into Christ have put on Christ.
28 There is neither Jew nor Greek, there is neither slave nor free, there is neither male nor female; for you are all one in Christ Jesus.
29 And if you are Christ’s, then you are Abraham’s seed, and heirs according to the promise.
all (v.26) — inclusive, whether circumcised or not
sons (v.26) — and, therefore, free from bondage to the law
through faith (v.26) — and not by circumcision
for (v.27) — not “and.” This verse isn’t in addition to verse 26 but because of verse 26.
baptized into Christ (v.27) — 1 Corinthians 12:13; Colossians 2:9-12. Not water baptism (Romans 6:3). If Paul had meant water baptism (an outward ritual), he would have been doing exactly what the Judaizers were doing.
put on (v.27) = clothed oneself with, as a stage actor takes on the dress and character of the person he portrays — but actual in this case
there is neither (v.28) = there cannot be. Neither national, social or gender distinction matter in salvation. All are one (one body) in Christ.
if you are Christ’s (v.29) — members of His Body
seed/heirs (v.29) — both lack the article because Gentiles weren’t the only seed.
Christ was Abraham’s seed and we are in Christ, so we are Abraham’s seed.