sand - retaining the metaphor of “the sea” (Isa 48:18).
like the gravel thereof - rather, as the Hebrew, “like that (the offspring) of its (the sea’s) bowels”; referring to the countless living creatures, fishes, etc., of the sea, rather than the gravel [Maurer]. Jerome, Chaldee, and Syriac support English Version.
his name ... cut off - transition from the second person, “thy,” to the third “his.” Israel’s name was cut off “as a nation” during the Babylonish captivity; also it is so now, to which the prophecy especially looks (Rom 11:20).