Question

How do we know that some pattern, rhythm, or meter was present in some of the Psalms?

Answer 1

Many musical words and notes are used in the
psalms.
Many psalms were sung.
Explanation:
"Psalms" is one of the 66 books in the Bible of
the Christian faith. They contain songs or
praise and worship which are mostly written
by David, the then king of Israel.
The name "Psalm' is derived from a Greek
translation, "psalmo'" meaning "instrumental
music, or words accompanying the music".
The psalms of the Bible are also lyrical songs of
praise that can be sung or recited as verses.
The presence of musical words, notes and the
very nature of the lyrics shows that there are
some patterns, rhythm or even meter in the Pslams.