User blog comment:EmpyreanSmoke/Supernatural Q&A (Closed)/@comment-172.101.67.105-20151117012137/@comment-168.169.25.92-20151117135219

That's not what Empyrean said. It's b.s. There's a reason, there's a difference between an angel blade, and an archangel blade. Castiel would've suggested stabbing Lucifer with an angel blade when they were trying to kill Lucifer.