'Sand of the Sea' in the Bible

I have let their widows be increased in number more than the sand of the seas: I have sent against them, against the mother and the young men, one who makes waste in the heat of the day, causing pain and fears to come on her suddenly.

As it is not possible for the army of heaven to be numbered, or the sand of the sea measured, so will I make the seed of my servant David, and the Levites my servants.