Praise the LORD, O Jerusalem; praise thy God, O Zion.
Praise the Lord, O Jerusalem. For he hath strengthened the bars of thy gates. The walls of Jerusalem had just been built, and the gates set up, under Nehemiah. This was the crowning of the secure re-establishment of the city and nation. This cycle of psalm was sung at the dedication of the walls (Nehemiah 3:1-32; Nehemiah 12:27-43). Compare Sir 49:13 , which seems to have had this passage in view, 'Nehemas, whose renown is great, who raised up for us the walls that were fallen down, and set up the gates and the bars, and raised up our ruins again.'
He hath blessed thy children within thee. Internal prosperity follows external security, which the building of the walls and setting up of the gates ensured.