出埃及记 17:2

² 所以与摩西争闹，说：给我们水喝罢！摩西对他们说：你们为甚麽与我争闹？为甚麽试探耶和华呢？

Uncover and grind meal

'To uncover' signifies adulterating the goods of the Word, and 'to grind meal' signifies falsifying its truths.