I’m reading an article by Frank Moore Cross about Hebrew prosody,* and he was talking about how, even after a couple centuries’ effort, no one has been able to find a consistent pattern of meter in classical Hebrew poetry — at least any meter like that of other classical poetry (namely, Greek and Latin), based on accent and stress. The main thing is that classical Hebrew poetry has lines of different length and irregular stress, while classical Greek and Latin poetry has strict rules for line length and stress. Cross proposes that the main feature of Hebrew meter is syllable count.
I think I might have a few ideas as to why classical Hebrew poetry doesn’t follow the strict metrical rules of classical Greek and Latin poetry. The first is the obvious: Hebrew poetry developed earlier than Greek poetry (and way, way before Latin poetry) and in a different cultural context, the poetry of which didn’t value strict adherence to set metrical patterns.
The second is the grammatical: the noun cases of Indo-European languages like Greek and Latin make it relatively easy to change the word order of the poetry to fit the rules of meter and still have an intelligible text. Hebrew doesn’t have a case system — at least nothing like the Indo-European languages — so it’s more difficult to shift word order and still have intelligible verse.
The third is the practical: the more you deviate from standard word order, the harder it is to understand you. It’s a fairly open question as to how easily Sophocles’ or Horace’s original audiences could have understood their works when listening to them. Hebrew poets, I think, kept more or less to standard word order, with the twin results that their poetry was easily understandable at first listen and also did not follow a rigid meter.
Thus, to sum up, Hebrew poetry did not follow classical rules of meter for three reasons: 1) It developed at an earlier time and in a different cultural context than Greek and Latin poetry; 2) Hebrew lacks the noun cases that allow Greek and Latin poetry to stray from standard word order to keep meter; 3) Hebrew poets kept mostly to standard word order in order to have verse that was easily understood by ear.
*Frank Moore Cross, “The Prosody of Lamentations 1 and the Psalm of Jonah.” Pages 99-134 in From Epic to Canon: History and Literature in Ancient Israel. Baltimore: Johns Hopkins, 1998.