When you're financing terrorism on a global scale...ya need cash reserves.
http://www.marketplace.org/2016/03/09/world/saudi-arabia-needs-money-really
and another take...
https://sg.finance.yahoo.com/news/heres-latest-sign-just-huge-234036927.html
Let's not mince words though...they're fine financing it...but to dedicate their army?
Oh, they'll set up madrassas all over the globe where it reaches even here in the US...and pay for it...but now that Iran is able to bring it's oil online and is really the powerhouse of the Middle East this threatens the power structure. That's why they need more money. Gotta keep the bread and circuses happening. Gotta keep the conscripts fed and armed. Gotta keep on converting more mindless religious zealots...gotta have more cash.
Remember Clinton wanted the Arab Spring, yet when the youth of Iran were at the precipice of another Bay of Pigs (which is most likely what she wanted!) they were too smart to take the bait and stood down...reluctantly. No, make no mistake the chickens are coming home to roost.