Set in Season 4 ep 22?

Dean'd come back! Sam was thrilled. The little boy who still believed Dean could fix anything was relieved, they'd be safe now!

'Go to him!' and impatient female voice whispered, she was dying slowly, had been since Dean's death. He was about to too, run and open the door so he and Dean could leave this place together, as brothers.

'Yes!' the voice exclaimed louder and soon as his thoughts were clear. 'Go away from here with Dean!' Then he saw Ruby, yelling and carrying on like she was prone to, and focused at the task at hand again.

'No! Dean's here…go…to…Dean…leave…"the voice gave it one more quiet shot, but as soon as he returned to killing Lilith, the voice died.

As soon as he'd killed Lilith he listened in his mind…no his soul for that voice. All that returned from her spot in his soul was static and the sounds of weeping.

Slowly at first the voice started coming through the static quietly…then louder and louder. Every time Sam would think of something violent he wished to do, she'd do what she'd been doing for years and hoped to continue doing till Sam died. The voice would say 'That's wrong Sam, you can't do that it goes against everything you've learned.' And Sam wouldn't do it.

Can anyone tell me what the voice is?