Jesaja 11:13

But this calls to mind the present rent in the unity of the nation; and the third question very naturally arises, whether this rent will continue. The answer to this is given in Isa 11:13 : "And the jealousy of Ephraim is removed, and the adversaries of Judah are cut off; Ephraim will not show jealousy towards Judah, and Judah will not oppose Ephraim." As the suffix and genitive after tzōrēr are objective in every other instance (e.g., Amo 5:12), tzorerē Yehudâh must mean, not those members of Judah who are hostile to Ephraim, as Ewald, Knobel, and others suppose, but those members of Ephraim who are hostile to Judah, as Umbreit and Schegg expound it. In Isa 11:13 the prophet has chiefly in his mind the old feeling of enmity cherished by the northern tribes, more especially those of Joseph, towards the tribe of Judah, which issued eventually in the division of the kingdom. It is only in Isa 11:13 that he predicts the termination of the hostility of Judah towards Ephraim. The people, when thus brought home again, would form one fraternally united nation, whilst all who broke the peace of this unity would be exposed to the immediate judgment of God (yiccârēthu, will be cut off).

It is a very good transition in prophecy (whether it be so in rhetoric or no), and a very common one, to pass from the prediction of the temporal deliverances of the church to that of the great salvation, which in the fulness of time should be wrought out by Jesus Christ, of which the other were types and figures, to which all the prophets bore witness; and so the ancient Jews understood them. For what else was it that raised so great an expectation of the Messiah at the time he came. Upon occasion of the prophecy of the deliverance of Jerusalem from Sennacherib, here comes in a prophecy concerning Messiah the Prince. I. His rise out of the house of David (Isa 11:1). II. His qualifications for his great undertaking (Isa 11:2, Isa 11:3). III. The justice and equity of his government (Isa 11:3-5). IV. The peaceableness of his kingdom (Isa 11:6-9). V. The accession of the Gentiles to it (Isa 11:10), and with them the remnant of the Jews, that should be united with them in the Messiah's kingdom (Isa 11:11-16) and of all this God would now shortly give them a type, and some dark representation, in the excellent government of Hezekiah, the great peace which the nation should enjoy under him, after the ruin of Sennacherib's design, and the return of many of the ten tribes out of their dispersion to their brethren of the land of Judah, when they enjoyed that great tranquility.

11:13 jealousy between Israel and Judah: The two kingdoms had become enemies during Judah’s war with the alliance of Syria and Israel (see 7:1-12). In the future, they would cooperate in joint military expeditions.