# On the night before Herod was going to bring him out for trial

That Herod planned to execute him can be clarified. AT: "The happened on the day before Herod was going to bring Peter out from prison to put him on trial and then to execute him" (See: [[rc://en/ta/man/translate/figs-explicit]])

# bound with two chains

"tied with two chains" or "fastened with two chains." Each chain would have been attached to one of the two guards who stayed beside Peter.

# were keeping watch over the prison

"were guarding the prison doors"