Thinketh to have confidence (δοκε πεποιθενα). Second perfect active infinitive. Old idiom, "seems to himself to have confidence." Later idiom like Matthew 3:9 "think not to say" and 1. Corinthians 11:16, "thinks that he has ground of confidence in himself."

I yet more (εγω μαλλον). "I have more ground for boasting than he" and Paul proceeds to prove it in the rest of verses Philippians 3:5; Philippians 3:6.

Circumcised the eighth day (περιτομη οκταημερος). "In circumcision (locative case) an eighth day man." Use of the ordinal with persons like τεταρταιος (John 11:39). Ishmaelites were circumcised in the thirteenth year, proselytes from Gentiles in mature age, Jews on the eighth day (Luke 2:21).

Of the stock of Israel (εκ γενους Ισραηλ). Of the original stock, not a proselyte.

Benjamin (Βενιαμιν). Son of the right hand (that is, left-handed), son of Rachel. The first King, Saul (Paul's own Hebrew name) was from this little tribe. The battle cry of Israel was "After thee, O Benjamin" (Judges 5:14).

A Hebrew of the Hebrews (Εβραιος εξ Εβραιων). Of Hebrew parents who retained the characteristic qualities in language and custom as distinct from the Hellenistic Jews (Acts 6:1). Paul was from Tarsus and knew Greek as well as Aramaic (Acts 21:40; Acts 22:2) and Hebrew, but he had not become Hellenized.

A Pharisee (Φαρισαιος). In distinction from the Sadducees (Galatians 1:14) and he continued a Pharisee in many essential matters like the doctrine of the resurrection (Acts 23:6). Cf. 2. Corinthians 11:22.