Egypt’s sin is closely connected to Israel. Egypt is described as a staff made of reeds. A reed staff looks strong but breaks easily.
Egypt claimed it would support Israel, but it did not have the power or the will to help. It encouraged Israel to rebel against Assyria and Babylon but did not provide real help (compare 2 Kings 18:21).
Israel sinned by trusting in this weak support. But Egypt was also guilty. It gave false hope and would face God’s judgment.