A.T. Robertson Commentary Acts 12:18

"Now as soon as it was day, there was no small stir among the soldiers, what was become of Peter." — Acts 12:18 (ASV)

As soon as it was day (Γενομενης ημερας). Genitive absolute, day having come.

No small stir (ταραχος ουκ ολιγος). Litotes (ουκ ολιγος), occurs eight times in the Acts as in 15:2, and nowhere else in the N.T. Ταραχος (stir) is an old word from ταρασσω, to agitate. In the N.T only here and 19:23. Probably all sixteen soldiers were agitated over this remarkable escape. They were responsible for the prisoner with their lives (cf. Acts 16:27; 27:42). Furneaux suggests that Manaen, the king's foster-brother and a Christian (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 (τ αρα ο Πετρος εγενετο). An indirect question with the aorist indicative retained. Αρα adds a syllogism (therefore) to the problem as in Lu 1:66. The use of the neuter τ is different from τις, though nominative like Πετρος, literally, "what then Peter had become," "what had happened to Peter" (in one idiom). See the same idiom in Joh 21:21 (ουτος δε τ).

But this one what (verb γενησετα not used).