What did Adam's sin do to the entire human race?
Adam's sin plunged the entire human race into a fallen spiritual condition, making all people carnal and sold under the old Adamic nature. Every offspring inherits that sin nature, so Christ had to die to bring fallen mankind back to Himself.
Les explains that the law is spiritual, but Paul was carnal, a son of Adam, sold under the old Adamic nature or under sin. When Adam fell, he plunged the whole human race into that condition, so Christ had to die to bring fallen mankind back to Himself. Les notes that some might object, asking how God could call them a sinner because of what Adam did 6,000 years ago. He cannot answer that, but he affirms God's mind is higher than our minds and His thoughts higher than our thoughts. God sovereignly set it in motion, placing Adam and Eve in the garden and giving them one simple responsibility: not to eat of that one tree. It was merely a means of testing their obedience; nothing was wicked in the fruit. Adam flunked totally, ate, and a sovereign God declared that all his offspring would inherit that sin nature.