There’s a phenomenon called the rhyme-as-reason effect that says people are more likely to believe something is true if it rhymes. A 2000 study published in the journal Psychological Science with the excellent title Birds of a Feather Flock Conjointly examined this phenomenon. 100 volunteers were given aphorisms that either rhymed (“Life is mostly strife”) or were modified to not rhyme (“Life is mostly struggle”) and asked to rate them for accuracy. The group that was given the rhyming versions rated them as more accurate.

That’s why “If it doesn’t fit, you must acquit” worked for Johnnie Cochran a lot better than “If it doesn’t fit, you must find my client not guilty” probably would have.