Charles Ellicott Commentary Acts 12:10

"And when they were past the first and the second guard, they came unto the iron gate that leadeth into the city; which opened to them of its own accord: and they went out, and passed on through one street; and straightway the angel departed from him." — Acts 12:10 (ASV)

When they were past the first and the second ward.—It would seem from this that Peter had been placed in the innermost dungeon, and had to pass the two courtyards. Lightfoot supposes the prison to have been between the inner and outer walls of the city, the direction of Peter’s movements being from the outer to the inner.

The iron gate.—The touch of topographical precision may be noticed as characteristic of St. Luke.

Passed on through one street.—The word implies one of the narrow streets or lanes of the city. (See Note on Matthew 6:2.)