The jailer was about to kill himself either for a point of military honor or, more likely, because of the reason given in 12.19: that a jailer who allowed prisoners to escape would receive the same punishment due the prisoners. It may be useful to have at this point some marginal note to explain that the jailer’s intention to kill himself was based upon the fact that in ancient times a jailer who allowed prisoners to escape would receive their punishment, and, in view of the fact that evidently some of the prisoners were slated for capital punishment, the jailer assumed that he himself would be killed. Otherwise, such an action would be regarded as quite incomprehensible in some societies.

Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on The Acts of the Apostles. (UBS Handbook Series). New York: UBS, 1972. For this and other handbooks for translators see here .