I'm sorry, this guy's supposed to set "the hardest crosswrods there are" but that clue is dreadful.
10 is a number, yes, but a large one? i don't think so.
If it is is 9 a large number? i mean it's only one less.
And shouldn't it be "in Jerusalem, for example"
The clue gives the solver to expect that there is something specific about Jerusalem rather than an enormous group of which jerusalem is just one.
On that basis he could have used the name of just about any choral piece!
I'm unimpressed