"...All the ends of the earth have seen the salvation of our God."
~ Psalm 98:3b
A psalm of salvation (v.1-3), musical worship (v.4-8) and ultimate justice (v.9). And this is why we gather as the church. We gather because of, by means of and for the praise of the freedoms we have in Christ from the salvation (forgiveness of sins) that he provides. This is our gospel message!
This is another psalm that is very fitting as a call to worship. Read and have your heart and mind directed in this way. God has done marvelous things; his arm is strong and has worked salvation (v.1). He has revealed himself, his salvation and his righteousness to us (v.2). His love for us is steadfast and he never forgets it (v.3). He is the righteous and just judge of all the earth (v.9; Ps. 96:10,13).
We should join with all creation in the worship of its Creator (v.4,7-8). We can and should use the instrument of human voice and the various instruments of human invention (v.5-6). And the noise produced must be joyful and melodious (v.4-6).
Sing to the LORD, oh you his people!