Charles H. Spurgeon on Psalms 33:3

A new song. That is to say, a new and recent composition on account of recent benefits; or constantly new songs, song succeeding song as daily new material for divine praise offers itself to the attentive student of the works of God. Or new, that is, always fresh and full of life, and renewed as new occasions offer themselves: as Job says, "My glory was fresh in me, and my bow was renewed in my hand." Or new, i.e., not common but rare and exquisite; as the new name in Re 2:17; the new commandment; Joh 13:34. Or this respects the gospel state, wherein is a new covenant Heb 8:8, a new Jerusalem Re 21:2, a new man Eph 2:15, and all things new, 2Co 5:17. New, on account of its matter being unknown of men: as in Re 14:3, "They sung a new song, "and no man could learn that song but the hundred and forty and four thousand, which were redeemed from the earth. New may be used in opposition to old. The song of Moses is old, and of the Lamb is new. Martin Geir (1614-1681), in "Poli Synopsis Criticorum."