H4: Comma with Non-Essential Elements Inside a Sentence: Use a pair of commas in the middle of a sentence to set off clauses, phrases, and words that are not essential to the meaning of the sentence, including words to indicate direct address. Use one comma before to indicate the beginning of the pause and one at the end to indicate the end of the pause. See Writing for Success Section 3.1 pp. 104-105 or RULE 4, 5 & 6 of the following: https://www.iue.edu/hss/writingcenter/documents/Commas.pdf
Clause in the middle:
John Milton, who wrote about the war between God and Satan in Paradise Lost, modeled his epic on Virgil’s Aeneid.
Parenthetical phrase in the middle:
New Year’s Day, of course, can be a painful one for many.
Phrase of contrast in the middle:
Esmerelda, unlike Edna, liked the blue hair dye.
Word of direct address in the middle:
If one were to ask others, Richard, you’d see that there are multiple options available.