C. F. Keil and Franz Delitzsch on Psalms 150:6

Psa 150:6

The call to praise has thus far been addressed to persons not mentioned by name, but, as the names of instruments thus heaped up show, to Israel especially. It is now generalized to “the totality of breath,” i.e., all the beings who are endowed by God with the breath of lie (Hebrew_Bible_נשׁמת חיּים), i.e., to all mankind.

With this full-toned Finale the Psalter closes. Having risen as it were by five steps, in this closing Psalm it hovers over the blissful summit of the end, where, as Gregory of Nyssa says, all creatures, after the disunion and disorder caused by sin have been removed, are harmoniously united for one choral dance (εἰς μίαν χοροστασίαν), and the chorus of mankind concerting with the angel chorus are become one cymbal of divine praise, and the final song of victory shall salute God, the triumphant Conqueror (τῷ τροπαιούχῳ), with shouts of joy. There is now no need for any special closing beracha. This whole closing Psalm is such. Nor is there any need even of an Amen (Psa 106:48, cf. 1Ch 16:36). The Hallelujah includes it within itself and exceeds it.