Peace be within thy walls - The word here rendered walls, means properly an host, an army; then a fortification, an entrenchment, especially the ditch or trench with the low wall or breastwork which surrounds it. Gesenius, Lexicon. It refers here to the fortifications or defenses around Jerusalem.
And prosperity - Peace; the same word which is used in the previous verse, and expressing the same idea - that of tranquility.
Within thy palaces - This word properly means a “fortress,” “castle;” then, a palace, a residence of a king or a prince, 1 Kings 16:18; 2 Kings 15:25; Isaiah 25:2. The idea is, that such places abounded in Jerusalem; and the prayer is, that in those abodes of power, where the rulers of the land resided, there might be peace. The particular reason for this prayer is suggested in the following verse.