Acts 3:15

ἀρχηγὸν τῆς ζωῆς, the prince of life. The same word applied to Jesus (Hebrews 12:2) is rendered ‘author and finisher of our faith,’ and in the same epistle (Acts 2:10) ‘the captain of their salvation.’ It is probably in the latter sense that St Peter, whose thoughts are on the resurrection, uses the word here, thinking of Christ as the firstfruits of them that slept (1 Corinthians 15:20), but the other sense, that ‘in Him was life’ (John 1:4), is also embraced in the word.

ἤγειρεν, raised, i.e. once for all.

οὗ. This pronoun takes up the preceding ὅν, and refers to Jesus, ‘whose witnesses we are.’ Not merely of the Resurrection did the Apostles bear witness, but of all Christ’s teaching and deeds. Cf. Acts 1:22, where Matthias was chosen to be such a witness.