"It is. And the reason why Azazel had Jessica killed and why Lucifer himself tried to make certain you were dead." Because, even if Gabriel hadn't figured out the soul ties between himself and his humans, Lucifer had.

But, then, Lucifer was meant to be more tied to Sam.

"It is also why Lucifer's forces made certain to take out the Harvelle women as well." He couldn't be clearer about Dean's soul ties. "The only reason he wasn't as lost to despair over losing his soulmates is because he was never given the chance to meet the angelic one until now."