Psalms 145:21

Let all flesh bless his holy name - He is good to all, wants to save all, actually feeds and preserves all. And as near as שמר shamar is to שמד shamad, so near is he a Savior to those who stand on the brink of destruction, if they will look to him.

For the application of all this Psalm to the Church of Christ, see the analysis.

My mouth shall speak the praise of the Lord - That is, I will utter his praise. In view of all these things, in view of his character and doings, I will praise him. I will be found among those who honor him; who acknowledge him as the true God; who render homage for what he is, and thanks for what he has done.

And let all flesh bless his holy name forever and ever - All people; all that dwell upon the earth. Let his praise be universal and eternal. This is the language of true piety; all in whose bosom there is any true religion will heartily say Amen. No desire of a pious heart is more constant and strong than that God should be praised, adored, honored by all intelligent creatures; that he should be known and acknowledged in all the earth as the true God; that his praise should ascend from all parts of the universe forever. See the notes at Psalm 100:1-5.