Gabriel opened his mouth to reply, but shut is as Lucifer continued. He'd figured out everything his older brother had. Neither Winchester would let the other be a permanent vessel for the Archangel. Sooner or later though, Jimmy would burn out, and he couldn't let that happen.
Castiel was his brother just as much as Lucifer was, and both of them had already been through enough.
"New plan, huh?" He lifted his gaze to meet his brother's again. "Find another vessel, and don't be looking at mine."