NO COPYRIGHT infringement intended. I DO NOT OWN CW's Supernatural. Nor am I making any money off this. Just sharing some of my favorite scenes from the series. Warnings: Language, Edited Supernatural Season 11
When I think about it, Lucifer is constantly holding back against them. Exhibit A: we've seen him shove his fist straight through a person before but he doesn't break their skulls open with a single hit?
Lucifer remarks, "Feels like I'm human" in the cage, implying his powers are greatly reduced. Meanwhile Lucifer isn't trying to kill them, he needs them to get out, so he's trying to intimidate them. He needs them alive - if only so he can play with them.
Jimmy Novak was devout - and Castiel benefitted much from Jimmy's memories. Like Michael, who's attitude changed when inhabiting Adam, Jimmy provided Castiel with motivation, skills and an already healthy vessel. God boosted him upon his revival(s) and Castiel was known to be a front-line angel in many conflicts, enough Naomi had to drill him more than any other angel. When Lucifer absorbs Castiel, he not only gets Jimmy's body, but also Castiel's subservience. Jimmy also has no soul currently, which while troubling, means Castiel / Lucifer have zero opposition from his body and it's not housing unstable elements. This is unique, as Castiel essentially became the only thing powering that vessel - it'd be like throwing Jimmy out of the Impala - it's lighter, it's faster. This likely could only occur because of Cas's unique resurrection.