From the wretched state of the idolatrous nations around, Israel, as a nation of Priests and Levites to the Lord, is called upon to mark its distinguishing blessings, and to make a proper use of them; and then the Psalm ends, as, it began, with Hallelujah!
Related Commentaries of Psalms 135:19
Psalms 135:19-21
19 Bless the LORD, O house of Israel: bless the LORD, O house of Aaron:
20 Bless the LORD, O house of Levi: ye that fear the LORD, bless the LORD.
21 Blessed be the LORD out of Zion, which dwelleth at Jerusalem. Praise ye the LORD.