RobH_en_tn/psa/069/015.md

the deep water ... the floods of water ... the deep

These phrases mean the same thing. (See: rc://en/ta/man/translate/figs-parallelism)

the floods of water overwhelm me

The writer speaks about his danger from his enemies as if flood waters were covering him completely. (See: rc://en/ta/man/translate/figs-metaphor)

the deep swallow me up

The writer speaks of the deep as if it was a deadly animal that was about to eat him. AT: "the deep waters swallow me up like a dangerous animal" (See: rc://en/ta/man/translate/figs-personification and rc://en/ta/man/translate/figs-metaphor)

Do not let the pit shut its mouth on me

Here the "pit" is spoken of as if it has a mouth like a person and could eat the writer. AT: "Do not let the pit consume me" or "Do not let the pit of death close over me" (See: rc://en/ta/man/translate/figs-personification and rc://en/ta/man/translate/figs-metaphor)