An artist's representation of Rehoboam having none of that sass.
Instead, Rehoboam consults with "the young men who had grown up with him" (i.e., his frat bros), who advise him on how to handle the situation:
"... thus shalt thou say unto them, My little finger shall be thicker than my father's loins. And now whereas my father did lade you with a heavy yoke, I will add to your yoke: my father hath chastised you with whips, but I will chastise you with scorpions." (1 Kings 12:10-11, King James Version)
Yeah, we've all been there: You're shooting the shit with your drinking buddies, they persuade you to boast about the size of your dong, and Israel gets into a 17-year civil war. Now, some of you have rushed to your Bibles and found that your translation is the much tamer "My little finger shall be thicker than my father's waist," but that's apparently an incorrect translation -- or a less crude version, anyway. The same word is used elsewhere in the Bible to mean "penis." The message is clear: "My little finger is bigger than my dad's cock, so you can just imagine what I'm packing."
"I'm not sure how that 'whipping people with scorpions' thing works out, but BY GOD I WILL FIND A WAY."
In other words, Rehoboam's response to a plea for mercy was to initiate a posthumous dick-measuring contest with a king who was famously able to satisfy a harem of 1,000 women. And hey, speaking of Solomon's legendary privates ...