FORTRESS
The terms “fortress” and “castle” refer mainly to a part of the city more strongly fortified than by mere walls.
Pr. 18:19 speaks of “fortress bolts.”
When Jerusalem was taken by David, there was already a citadel, defended by the Jebusites (2 Sam. 5:6, 7).
The Romans had a fortress in Jerusalem, to which Paul was taken when he was captured by the Jews (Acts 21:34, 37).
It could have been the so-called Antonia Tower, which had been built by Herod the Great. As Josephus describes it, it was adjacent to the Temple (Wars, 5:5, 8).
The psalmist frequently describes Jehovah as his rock and fortress or castle (Ps. 18:2; 31:3; 71:3; 91:2).