Shall the instrument boast against Him who uses it? Through free in a sense, and carrying out his own plans, the Assyrian was unconsciously carrying out God’s purposes.
shaketh it - moves it back and forward.
staff ... lift ... itself ... no wood - rather, “as if the staff (man, the instrument of God’s judgments on his fellow man) should set aside (Him who is) not wood” (not a mere instrument, as man). On “no wood” compare Deu 32:21, “that which is not God;” Isa 31:8 shows that God is meant here by “not wood” [Maurer].