What is your favorite Biblical idiom ?

"son of man" - it basically means "a human being".

"many" - this actually means "all" or "the multitude" "This is my blood of the new covenant, shed for you and for many".

One of my favorites is "talent"

that which has weight but is useless if not along with something else for honest measure

I rather like the idea of doing something by "the skin of your teeth"

I also like girding the loins. I always picture a guy with his pants falling down yanking them up.

'To kick against the goads' (as per Acts 26:14)