The word "parallel" refers to elements that are either similar in nature or have a relationship to each other. Parallelism is a feature of Hebrew poetry where a particular line is repeated, advanced or contrasted with another idea. Multiple words might refer to a single object in the poem. For example, a poem may include the words "soul" and "heart" and have both words refer to a specific person. When different lines contradict each other, the later line may disprove the former line, or the contrast may show that a particular assertion is true under some circumstances, while being false under others. Additional lines not only clarify earlier lines, but also build upon these lines. Parallel structures can extend beyond multiple verses or can even extend beyond several chapters.
In terms of structure, poetry in English tends to focus more on rhyming and meter, while Hebrew poetry focuses more on parallelism. Hebrew poetry does not have set rules and can exhibit flexibility. However, some forms of parallelism are alphabetic. For example, each line of the poem could begin with a different letter of the Hebrew alphabet.
Hebrew poetry is often broken into sections called "thoughts." The thoughts are broken up into "periods" that contain lines or segments. When different periods exhibit parallelism, they are grouped together as strophes.
Many parallelisms cannot be translated into English, so only those who read the poems in the original Hebrew understand the puns. Those translating Hebrew do not always notice the parallelism, which causes them to translate passages inaccurately.
Parallelism is common in the Old Testament. In terms of poetic passages, this feature is most common in Proverbs and Psalms. Parallelism indicates the message communicated by the passage is in the overall passage, rather than in the individual lines. In addition, parallelism clarifies parts of the poem that seem ambiguous initially.
Parallelism is not only in Hebrew poetry. It is also common in poetry from around the world, and can even be found in everyday speech. However, the parallelism found in everyday speech is rarely identified as poetry. When someone uses repetition or makes seemingly contradictory statements, that person is using parallelisms.