When Hell freezes over ...

Hell freezes over ... things ex-l actually agrees with Dadi Janki (a) and BapDada (b) on.

a) Be accurate (... if you are going to shoot your mouth off, get your facts right)
b) Be essenceful (... please get to the point and stick to it)

Hell is meant to be a very hot place full of fire (and devils) ... so the joke is, it can never freeze over. For non-English speakers, we say "Hell freezes over" when something surprising and extremely unlikely happens.