As soon as it was day (Genomenēs hēmeras). Genitive absolute, day having come.
No small stir (tarachos ouk oligos). Litotes (ouk oligos), occurs eight times in the Acts as in Act 15:2, and nowhere else in the N.T. Tarachos (stir) is an old word from tarassō, to agitate. In the N.T only here and Act 19:23. Probably all sixteen soldiers were agitated over this remarkable escape. They were responsible for the prisoner with their lives (cf. Act 16:27; Act 27:42). Furneaux suggests that Manaen, the king’s foster-brother and a Christian (Act 13:1), was the “angel” who rescued Peter from the prison. That is not the way that Peter looked at it.
What was become of Peter (tōi ara ho Petros egeneto). An indirect question with the aorist indicative retained. Ara adds a syllogism (therefore) to the problem as in Luk 1:66. The use of the neuter tōi (as in Act 13:25) is different from tis, though nominative like Petros, literally, “what then Peter had become,” “what had happened to Peter” (in one idiom). See the same idiom in Joh 21:21 (houtos de tōi).