Charles H. Spurgeon on Psalms 135:20

Ye that fear the LORD, bless the LORD. These are distinct from the Israelites, priests, and Levites, and design the proselytes among them of other nations that truly feared God, as Jarchi notes; and all such persons, whoever and wherever they are, have reason to bless the Lord for the fear of him they have, which is not from nature but from grace; and for the favours shown them, the blessings bestowed upon them, the good things laid up for them, and the guard that is about them, which the Scriptures abundantly declare, and experience confirms. —John Gill.