98:1-3 God's own arm has brought salvation and all the earth witnesses His lovingkindness and faithfulness to Israel.

98:4-6 All the earth is called to praise God
When a king came to the throne there was a ceremony with blowing of trumpets and shouting (I Sam. 10:24; I Kings 1:39-40) and clapping of hands (II Kings 11:12). All nature responds this way to God’s kingship.

98:7-9 There are slight differences with Psalm 96:11-13. “Instead of the heavens and earth, this psalm has the world and all who live in it (a phrase found elsewhere only in 24:1, a psalm of temple entry that also celebrates Yahweh as the King). Instead of the fields and the forest, this psalm has rivers and the mountains. Instead of Yahweh’s judging ‘the peoples in truth’ (lit. faithfulness), He does so here with equity” Broyles, 382. 

Psalm 98 and Jesus
98:1 New song- Rev. 5:9; 14:3
98:1 He has done marvelous things- Rev. 15:3
98:1 Arm of the LORD- Isaiah 52:10; 53:1
God’s power and holiness combine to bring victory (salvation)- I Cor. 1:22-24. God is just and justifier of the One who has faith in Jesus- Romans 3:21-26
98:2 Righteousness revealed- Rom. 1:17 it has been revealed to all nations- Jews and Greeks.
98:2-3 Salvation- Titus 2:11
98:3 Mercy remembered- Luke 1:54
98:3 Truth- John 14:6
98:3 Ends of earth beheld salvation- Rom. 10:18
98:9 Coming to Judge the world in righteousness- Acts 17:30-31; John 12:48
Exalted to God’s right hand- Psalm 110:1; Acts 2:29-36