Lucifer was an angel, Sam was a human. Plain and simple. Sam had already endured Lucifer relentless and torturing hands hands for centuries. He knew what to expect.
But knowing didn't make it hurt any less.
So when Lucifer's fists started swinging and pummeling into him, Sam still fell to his knees.
The same hands that had just beat him grabbed him by the collar, one snaking out to lift his chin, forcing him to stare into Lucifer's eyes.
"I have broken you before, Sam Winchester. I have no problem doing it again."
Sam clenched his teeth, and hissed, "No."