The rod of his anger - That with which he smites others (compare Isaiah 14:6). The King James Version describes the final impotence of the wrath of the wicked.

He that soweth iniquity - The crop must be according to the seed. If a man sow thistle seed, is it likely he shall reap wheat? If he sow to the flesh, shall he not of the flesh reap destruction?

He that soweth iniquity shall reap vanity: and the (e) rod of his anger shall fail.
(e) His authority by which he oppressed others, will be taken from him.

He that soweth iniquity (u) shall reap vanity,.... He that practises sin, and is frequent in the commission of it; indulges to it in a profuse way, as the sower plentifully scatters his seed; such shall reaper possess nothing but sin and wickedness; for, what a man sows, that shall he reap; he shall eat the fruit of his doings, and have the reward of his works; see Job 4:8; or "nothing" (w), mere emptiness; it shall not answer; he shall have in the end neither pleasure nor profit, but the contrary; "shall reap evil things", as the Septuagint, Arabic, and Vulgate Latin versions render it;
and the rod of his anger shall fail; with which he has ruled and smitten others in an angry and cruel manner; this shall be taken from him; his authority shall fail, and he shall become subject to others, and be used in like manner; see Isaiah 14:4. R. Joseph Kimchi interprets it of "the rod of the increase" of the earth, or the rod or flail with which the fruits of the earth are threshed or beaten out, which should fail before they were reaped; and Schultens (x) has reference to the same, and gives the sense, that a wicked man that sows iniquity, when he thinks his harvest is ripe, shall be beaten with the flail, by which he shall be consumed; and he that threshed others shall be threshed himself.
(u) So, "serere fallaciam", in Plauti Poenulo, l. 1. v. 67. (w) "inanitatem ac nihilum", Michaelis. (x) "Et virga in eum desaevitura, erit decretoria".

The power which many abuse, will soon fail them.

(Compare Proverbs 11:18; Psalm 109:16-20; Galatians 6:7-8).
the rod . . . fail--His power to do evil will be destroyed.

The group now following extends to the end of this first collection of Solomon's proverbs; it closes also with a proverb of the poor and the rich.
8 He that soweth iniquity shall reap calamity;
And the rod of his fury shall vanish away.
"Whatsoever a man soweth, that shall he also reap" (Galatians 6:7); he that soweth good reapeth good, Proverbs 11:18; he that soweth evil reapeth evil, Job 4:8; cf. Hosea 10:12. עולה is the direct contrast of צדקה or ישׁר (e.g., Psalm 125:3; Psalm 107:42), proceeding from the idea that the good is right, i.e., straight, rectum; the evil, that which departs from the straight line, and is crooked. Regarding און, which means both perversity of mind and conduct, as well as destiny, calamity, vid., Proverbs 12:21. That which the poet particularly means by עולה is shown in 8b, viz., unsympathizing tyranny, cruel misconduct toward a neighbour. שׁבט עברתו is the rod which he who soweth iniquity makes another to feel in his anger. The saying, that an end will be to this rod of his fury, agrees with that which is said of the despot's sceptre, Isaiah 14:5.; Psalm 125:3. Rightly Fleischer: baculus insolentiae ejus consumetur h. e. facultas qua pollet alios insolenter tractandi evanescet. Hitzig's objection, that a rod does not vanish away, but is broken, is answered by this, that the rod is thought of as brandished; besides, one uses כּלה of anything which has an end, e.g., Isaiah 16:4. Other interpreters understand "the rod of his fury" of the rod of God's anger, which will strike the עוּל and יכלה, as at Ezekiel 5:13; Daniel 12:7 : "and the rod of His punishment will surely come" (Ewald, and similarly Schultens, Euchel, Umbreit). This though also hovers before the lxx: πληγὴν δὲ ἔργων αὐτοῦ (עבדתו) συντελέσει (יכלּה). But if the rod of punishment which is appointed for the unrighteous be meant, then we would have expected כּלהו. Taken in the future, the כּלות of the שׁבט is not its confectio in the sense of completion, but its termination or annihilation; and besides, it lies nearer after 8a to take the suffix of עברתו subjectively (Isaiah 14:6; Isaiah 16:6) than objectively. The lxx has, after Proverbs 22:8, a distich: -
ἄνδρα ἱλαρὸν καὶ δότην εὐλογεῖ ὁ θεὸς
ματαιότητα δὲ ἔργων αὐτοῦ συντελέσει.
The first line (2-Corinthians 9:7) is a variant translation of 9a (cf. Proverbs 21:17), the second (ושׁוא עבדתו) is a similar rendering of 8b.

The rod - That power which he used with fury shall be taken from him.