But most commentators could be wrong, since the Bible does not say so directly. There are commentators who believe in fantastic rubbish like a secret rapture or an earthly millenial kingdom! There are commentators who fall on either side of the baptism debate. We cannot say something is sure because most commentators agree. Regarding what is a psalm itself, who's to say that the word cannot now nor ever did refer to an uninspired ditty? A song? a tune? an ode? a hymn? an anthem? See Tim Foster's word study a few posts back.