"Look" or "Listen." This word adds emphasis to what is said next. AT: "Pay attention to what I am about to tell you"
# stiffened their neck and refused to listen
These two phrases both speak of the people being stubborn. In the first phrase, Yahweh speaks of the people being stubborn as if they had made their necks stiff. AT: "stubbornly refused to listen" (See: [[rc://en/ta/man/translate/figs-parallelism]])