Answer
Synonymous parallelism is a poetic literary device which involves the repetition of one idea in successive lines. The first half of a verse will make a statement, and the second half will essentially say the same thing in different words. The statements are “parallel” in that they are juxtaposed, or side by side, and they often share similar syntax. The statements are “synonymous” in that they say the same thing, with some minor variations. Other types of parallelism found in Hebrew poetry include antithetical parallelism and synthetic parallelism, but synonymous parallelism is probably the most common.
In English poetry, one of the tools used is end rhyme:
“Out flew the web and floated wide;
The mirror crack’d from side to side”
(Tennyson)
End rhyme is formed by matching sounds; synonymous parallelism is formed by matching thoughts. English poets want their sounds to rhyme; Hebrew poets wanted their ideas to rhyme.
Psalm 120:2 is an example of synonymous parallelism:
“Save me, O Lord, from lying lips
and from deceitful tongues.”
The idea of “lying lips” in the first line of the poetry is repeated in the second line as “deceitful tongues.” The two expressions use different words to describe the same thing—a mouth that can’t tell the truth. The meanings of both lines are synonymous.
Proverbs 3:11 is another instance:
“My son, do not despise the Lord’s discipline
and do not resent his rebuke.”
“Do not despise” is equal to “do not resent”; the Lord’s “discipline” is synonymous with His “rebuke.” The first part of the command lines up rather neatly with the second part of the command. That’s synonymous parallelism.
Sometimes, the parallelism serves to amplify the theme as well as restate it. Take Proverbs 17:25, for example:
“A foolish son brings grief to his father
and bitterness to the one who bore him.”
In this proverb, the foolish son brings two things (“grief” and “bitterness”) to two people (his “father” and “the one who bore him,” i.e., his mother). The parallel structure links “grief” with “bitterness”—synonymous feelings of pain. And the father and mother are linked via parallelism, as well. The poet simply means “parents,” but he mentions them separately to fill out the poetic form. As a result, the point is made that both parents keenly feel the anguish of having a foolish son.
The prophetic books of the Old Testament also contain poetry. An example of synonymous parallelism is found in Isaiah 53:5:
“But he was pierced for our transgressions,
he was crushed for our iniquities.”
Isaiah predicts that the Messiah would suffer for “our transgressions,” a phrase synonymous with “our iniquities” in the next line. His suffering is referred to as a “piercing” and a “crushing.” These ideas are related but not exactly synonymous. They are set in parallel to give us a fuller picture of what the Messiah would experience on our behalf: a crushing load of sin (spiritual and emotional pain) and the piercing of the nails (physical pain).
When we read poetic portions of the Old Testament, we should look for the parallelism that helps to expand the thoughts presented and emphasize certain themes. To miss the parallelism is to overlook part of the beauty of the Bible.