Albert Barnes Commentary Zechariah 11:17

"Woe to the worthless shepherd that leaveth the flock! the sword shall be upon his arm, and upon his right eye: his arm shall be clean dried up, and his right eye shall be utterly darkened." — Zechariah 11:17 (ASV)

Woe to the idol shepherd - (A shepherd of nothingness, one who has no quality of a shepherd.) who leaveth the flock. The condemnation of the evil shepherd is complete in the abandonment of the sheep; as our Lord says, He that is an hireling and not the Shepherd, whose own the sheep are not, seeth the wolf coming and leaveth the sheep and fleeth: and the wolf catcheth them and scattereth the sheep. The hireling fleeth, because he is an hireling and careth not for the sheep. (John 10:12–13).

Or it may equally be, “Shepherd, you idol,” including the original meaning of nothingness, such as antichrist will be, (Jerome), “while he calls himself God, and wills to be worshiped.”

Jerome: “This shepherd shall therefore arise in Israel, because the true Shepherd had said, I will not feed you. He is prophesied of by another name in Daniel the prophet (Daniel 9:0), and in the Gospel (Mark 13:0), and in the Epistle of Paul to the Thessalonians (2 Thessalonians 2:0), as the abomination of desolation, who shall sit in the temple of the Lord, and make himself as God. He comes not to heal but to destroy the flock of Israel. This shepherd the Jews shall receive, whom the Lord Jesus shall slay with the breath of His mouth, and destroy with the brightness of His coming.”

The sword shall be upon (against) his arm and right eye. His boast shall be of intelligence and might. The punishment and destruction shall be directed against the instrument of each: the eye and the arm.

Jerome: “The eye, by which he shall boast to behold acutely the mysteries of God, and to see more than all prophets previously, so that he shall call himself son of God. But the word of the Lord shall be upon his arm and upon his right eye, so that his strength and all his boast of might shall be dried up, and the knowledge which he promised himself falsely shall be obscured in everlasting darkness.”

Dionysius writes: “Above and against the power of antichrist shall be the virtue and vengeance and sentence of Christ, who shall slay him with the breath of His mouth. The right arm, the symbol of might, and the right eye which was to direct its aim, should fail together through the judgment of God against him. He, lately boastful and persecuting, shall become blind and powerless, bereft alike of wisdom and strength.”

The “right” in Holy Scripture being so often a symbol of what is good, and the left of what is evil, it may also be imagined, that (Osorius), “the left eye, that is, the acumen and cunning to devise deadly frauds, will remain uninjured, while the right eye, that is, counsel to guard against evil, will be sunk in thick darkness. And so, the more he employs his ability for evil, the more frantically will he bring destruction upon himself.”