Abraham's circumcision as sign and seal (4:9–12)

Says Righteousness was credited to Abraham "not after, but before" his circumcision (4:10), and "he received the sign of circumcision as a seal of the righteousness that he had by faith while he was still uncircumcised" (4:11): σημεῖον … περιτομῆς, σφραγῖδα. Genesis calls circumcision "a sign of the covenant" (Gen 17:11), given when Abraham was ninety-nine (17:1, 24), after Gen 15:6 and after Ishmael's birth at eighty-six (16:16).

For circumcision as Israel's mark in Paul's world, see the note on 2:25–29. Here the question is Abraham's own order. Later Jewish teaching made his circumcision the completion of his righteousness: Rabbi (Judah the Prince) says that for all the commandments Abraham did, he was not called "complete" (shalem) until he was circumcised, citing "walk before Me and be blameless" (m. Ned. 3:11; Gen 17:1). Jubilees counts circumcision among the trials in which he "was found faithful" (Jub. 17:17–18). Philo presents Abraham, who left his ancestral gods, as the pattern for proselytes (Virt. 212–219).

The Epistle of Barnabas (c. 70–135) reports the claim that the people were circumcised as a seal (Barn. 9:6).

Implies The sign and seal confirmed a righteousness already credited and did not cause it (4:10–11), so Abraham is father of uncircumcised and circumcised believers alike (4:11–12).

Uncertain Whether Paul's "seal" draws on a Jewish usage already current is uncertain, since the explicit evidence comes later. For the use of 4:11 in baptism debates, see the Exegete's commentary.