Isaiah 42:13

It comes all to one whether we make these verses (as some do) the song itself that is to be sung by the Gentile world or a prophecy of what God will do to make way for the singing of that song, that evangelical new song. I. He will appear in his power and glory more than ever. So he did in the preaching of his gospel, in the divine power and energy which went along with it, and in the wonderful success it had in the pulling down of Satan's stronghold, Isa 42:13, Isa 42:14. He had long held his peace, and been still, and refrained himself, while he winked at the times of the ignorance of the Gentile world (Act 17:30), and suffered all nations to walk in their own ways (Act 14:16); but now he shall go forth as a mighty man, as a man of war, to attack the devil's kingdom and give it a fatal blow. The going forth of the gospel is thus represented, Rev 6:2. Christ, in it, went forth conquering and to conquer. The ministry of the apostles is called their warfare; and they were the soldiers of Jesus Christ. He shall stir up jealousy, shall appear more jealous than ever for the glory of his own name and against idolatry. 1.

— Matthew Henry's Concise Commentary (public domain)

Jehovah will no longer restrain His wrath: He will go forth as a mighty warrior (Exo 15:3) to destroy His people's and His enemies, and to deliver Israel (compare Psa 45:3). stir up jealousy--rouse His indignation. roar--image from the battle cry of a warrior.

— Jamieson-Fausset-Brown Commentary (public domain)