Let the sea roar, and the fulness thereof - See the notes at Psalm 96:11.
The world, and they that dwell therein - The habitable world - the land - in contradistinction from the sea. Let there be universal praise on the water and the land.

Let the sea roar - These are either fine poetic images; or, if we take them as referring to the promulgation of the Gospel, by the sea all maritime countries and commercial nations may be intended.

Let the sea roar, and the fulness thereof,.... See Gill on Psalm 96:11,
the world, and they that dwell therein; men, the inhabitants of the world; that is, let them rejoice because this glorious King has taken to himself his great power, and reigns, Revelation 11:15.

Here, too, it is all an echo of the earlier language of Psalm and prophets: Psalm 98:7 = Psalm 96:11; Psalm 98:7 like Psalm 24:1; Psalm 98:8 after Isaiah 55:12 (where we find מחא כּף instead of the otherwise customary תּקע כּף, Psalm 47:2; or הכּה כּף, 2-Kings 11:12, is said of the trees of the field); Psalm 98:9 - Psalm 96:13, cf. Psalm 36:10. In the bringing in of nature to participate in the joy of mankind, the clapping rivers (נהרות) are original to this Psalm: the rivers cast up high waves, which flow into one another like clapping hands;
(Note: Luther renders: "the water-floods exult" (frohlocken); and Eychman's Vocabularius predicantium explains plaudere by "to exult (frohlocken) for joy, to smite the hands together prae gaudio;" cf. Luther's version of Ezekiel 21:17.)
cf. Habakkuk 3:10, where the abyss of the sea lifts up its hands on high, i.e., causes its waves to run mountain-high.