"When they kept questioning him, he straightened up and said to them, 'Let any one of you who is without sin be the first to throw a stone at her.'" - John 8:7
We all fall prey to the subtle temptation to judge others based on our opinions, not thinking about our own wrongs in the process. Jesus warned against that in John 8, reminding us that those with sin may want to refrain from judging too hard.