Charles Ellicott Commentary Isaiah 11:4

"but with righteousness shall he judge the poor, and decide with equity for the meek of the earth; and he shall smite the earth with the rod of his mouth; and with the breath of his lips shall he slay the wicked." — Isaiah 11:4 (ASV)

With righteousness shall he judge the poor ... —The picture which Isaiah had drawn of the corrupt judges of his time gives point to the contrast (Isaiah 1:23; Isaiah 2:14–15; Isaiah 10:1–2). The poor whom they trampled on should be the special objects of the care of the true King (Matthew 11:5).

He shall smite the earth ... —The “earth” stands here, if we accept the reading, for the rulers who are for the time supreme in it. A slight alteration of the Hebrew gives shall smite the tyrant, which forms a better parallelism with the “ungodly” of the next clause. The phrase “the sceptre of his mouth” is significant. The word which the Messiah-King speaks shall be as the sceptre which is the symbol of authority. So in Revelation 1:16, “a sharp two-edged sword” comes forth from the mouth of the Christ of St. John’s vision. The latter clause, “with the breath of his lips shall he slay ...”, has a parallel in Hosea 6:5.