Why is this an important technique for him to use as he begins his argument

this quote could be referring to the death penalty. it's questioning the morality of sentencing murderers to death as a punishment, because it seems hypocritical. this quote seems to be arguing for non-lethal punishment for killers.

awnser:

jem is "moody and silent" after the pants incident. the new school year starts, and scout finds second grade just as boring as first. one day, she and jem are walking home together when jem reveals that when he found his pants that night, they were all folded up, and the tears had been crudely sewn up, as if someone knew that he would be coming back for them. he finds this highly eerie. then, they find a ball of twine in the radley oak tree knothole. again, they aren't sure if it is a gift for them or not, so they leave it for a few days. when it remains in the hole for a few days, they take it, and decide that anything left there is okay to take.