Acts 12:4

When he had apprehended him
When his officers he sent to take him had brought him:

he put him in prison;
in the common prison, very likely where he had been once before, ( Acts 5:18 )

and delivered him to four quaternions of soldiers to keep him;
each quaternion consisted of four soldiers, so that they were in all sixteen; and so the Syriac version renders it, "and delivered him to sixteen soldiers": how the Ethiopic version should make "seventeen" of them is pretty strange: these perhaps might take their turns to watch him by four at a time, two to whom he was chained, and two others to keep the doors; or all the sixteen together, being posted in one place or another for greater security: and it may be, that the reason of all this caution, and strong guard, might be, because it was remembered that he, and the rest of the apostles, when committed to the same prison some years ago, were delivered out of it:

intending after Easter,
or the passover,

to bring him forth to the people;
to insult and abuse him, and to put him to what death they should desire.