As long as you have a history of making the charitable contributions before you file, there shouldn’t be any problems putting the contribution into your budget for chapter 7 or 13. 10-15% of your gross won’t raise any objections. Congress would rather have you give money to the church than unsecured creditors.
Most churches keep track of your donations for tax purposes, so they will provide documentation of your past donations. Cancelled checks can also be used to prove a history. If you give cash, make sure to write you name on the little envelope so they can keep track. Your Federal taxes can also be used as proof of donations if you itemized your deductions. If you don’t have any records, start keeping them.