When he had taken him (piasas). See note on Act 3:7 for same form.
He put him in prison (etheto eis phulakēn). Second aorist middle indicative of tithēmi, common verb. This is the third imprisonment of Peter (Act 4:3; Act 5:18).
To four quaternions of soldiers (tessarsin tetradiois stratiōtōn). Four soldiers in each quaternion (tetradion from tetras, four), two on the inside with the prisoner (chained to him) and two on the outside, in shifts of six hours each, sixteen soldiers in all, the usual Roman custom. Probably Agrippa had heard of Peter’s previous escape (Act 5:19) and so took no chances for connivance of the jailors.
After the passover (meta to pascha). The passover feast of eight days. “The stricter Jews regarded it as a profanation to put a person to death during a religious festival” (Hackett). So Agrippa is more scrupulous than the Sanhedrin was about Jesus.
To bring him forth (anagagein auton). Second aorist active infinitive of anagō, to lead up, old verb, used literally here. Peter was in the inner prison or lower ward and so would be led up to the judgment seat where Herod Agrippa would sit (cf. Joh 19:13).
To the people (tōi laōi). Ethical dative, in the presence of and for the pleasure of the Jewish people.