When they had laid (επιθεντες). Second aorist (constative) active participle of επιτιθημ, to place upon.

Many stripes (πολλας πληγας). The Jewish law was forty stripes save one (2. Corinthians 11:24). The Roman custom depended on the caprice of the judge and was a terrible ordeal. It was the custom to inflict the stripes on the naked body (back) as Livy 2.5 says: "Missique lictores ad sumendum supplicium, nudatos virgis caedunt." On πληγας (from πλησσω, to strike a blow) see on Luke 10:30; Luke 12:47.

The jailor (τω δεσμοφυλακ). Late word (δεσμοσ, φυλαξ, keeper of bonds), in the N.T. only here (verses Acts 16:23; Acts 16:27; Acts 16:36). The LXX has the word αρχιδεσμοφυλαξ (Genesis 39:21-23). Chrysostom calls this jailor Stephanus, he was of Achaia (1. Corinthians 16:15).

To keep safely (ασφαλως τηρειν). Present active infinitive, to keep on keeping safely, perhaps "as dangerous political prisoners" (Rackham). He had some rank and was not a mere turnkey.