Whatever more shall be needful. Here the terms of the firman are very wide indeed, and authorise apparently an unlimited application of the royal revenue, or, at any rate, of the revenue of the province, to any purpose in any way connected with the temple.
Probably it was expected that Ezra's own discretion would act as a restraint. If this failed, the royal treasurers would see that the amounts specified in verse 22 were not exceeded. The king's treasure-house is not the royal treasury at Susa, to which the tribute went up from the various provinces, but the local treasury of Judaea or Syria, to which the Jews made their remittances, and on which Ezra was now authorised to draw.
Such local treasuries existed of necessity under a satrapial system.