(The verse numbering differs slightly between the English and Hebrew texts).
Hosea 12:8 (BHS/WHM 4.2)
8כְּנַ֗עַן בְּיָד֛וֹ מֹאזְנֵ֥י מִרְמָ֖ה לַעֲשֹׁ֥ק אָהֵֽב׃
Hosea 12:7 (ESV)
7 A merchant, in whose hands are false balances, he loves to oppress.
The verse comes abruptly and seemingly out of nowhere: note the context immediately before and after:
5 the Lord, the God of hosts, the Lord is his memorial name: 6 “So you, by the help of your God, return, hold fast to love and justice, and wait continually for your God.” 7 A merchant, in whose hands are false balances, he loves to oppress. 8 Ephraim has said, “Ah, but I am rich; I have found wealth for myself; in all my labors they cannot find in me iniquity or sin.” 9 I am the Lord your God from the land of Egypt; I will again make you dwell in tents, as in the days of the appointed feast. Hosea 12:5–9 (ESV)
Well, then, who is this “merchant”? Harper in the ICC for Hosea (1905) writes (page 384):
Canaan! Strophe 2 begins in a startling fashion, with the derogatory epithet – Canaan. The thought is a direct continuance of stophe 1 (1-4a)…. Canaan is not (1) an address, direct or indirect, to the Canaanites or Phoenicians, whose reputation for dishonesty was widely known; not (2) a common noun, merchant, for the work of merchandising in the cities had been in the hands of Canaanites so long that “Canaanite” had become a synonym for “merchant” ….To be rejected are (1) the making of h[nk an appositive of Ephriam (v. 9); (2) its treatment as a vocative; in favor of (3) the construction as an independent nominative or accusative.
Boice (Sermons on the Minor Prophets, vol. 1, page 98) explains:
There is a word in the Hebrew of verse 7 that is obscured in most English translations. It is the word Canaan or Canaanite, translated “merchant” in most instances ….This word stands first and isolated in verse 7, so that we could read, “Canaanite! He uses dishonest scales; he love to defraud. Ephraim boasts, I am very rich; I have become wealthy. With all my wealth, they will not find in me any iniquity or sin.” (Canaanite also means merchant, with an emphasis on being dishonest in trade, but by translating it “merchant” Hosea’s deliberate reference to the people of the land is obscured.)
The point is this. Before Israel settled in the land promised to them by God, the land was called Canaan. It was an abominable place. Not only was it a center for all types of commercial dishonesty; it was also notorious for its sexual and religious depravity. Cultic prostitution was common. People worshipped sexual organs. At times children were sacrificed to Canaan’s gods. “Canaan” meant depravity. When Israel was sent into Canaan under Joshua, she was given the task of rooting out this corruption and establishing a culture marked by holiness instead. Israel’s task was to make Canaan Israel. What happened? Canaan made Israel Canaan!
Staurt explains at more length:
8 8 has a format similar to certain ancient tribal “blessings” (cf. e.g. Gen 49:13, 16, 19, 20, 21, 27). The name appears in the initial position of the sentence, and a metaphorical description follows. Here, as in some other “blessings,” the description is hardly flattering (cf. Gen 49:5–7, 17, 27). “Canaan” would appear to be a derogatory double entendre for Ephraim. “Canaanite” could mean not only an inhabitant of the promised land (“Canaan” derives originally from the name of the Phoenician coast) but also a “trader” or a “merchant” (cf. Job 40:30; Prov 31:24; Ezek 17:4; Zeph 1:11) as the Phoenicians were associated with long-distance commercial trade. By this metaphor, Hosea declares Ephraim to be a greedy merchant, and at the same time no better than the Canaanites whose immoral culture deserved extinction (cf. Gen 15:16). Amos portrays the north similarly (Amos 8:4–6). Ephraim’s control of key north-south trade routes and its agricultural productivity (cf. 2:10 ) gave it a prosperity, but one enjoyed only by the upper classes. The poor failed to share in the wealth.
“Fraudulent scales” (מאזנימרמה) were a dishonest merchant’s key tools. They became symbolic in OT literature of unscrupulous dealings (Deut 25:13; Prov 11:1; 20:23; cf. Mic 6:11). “Canaan” is thus one who loves to “oppress” (עשק). Hosea employed עשק in 5:11 to foretell in accordance with the covenant curse predictions (Deut 28:29, 33) that Ephraim would be “oppressed.” Here, however, the verb is used to help portray before the court, as part of the covenant lawsuit, the despicable character of the nation deserving such a fate. The term is used especially to signify keeping the downtrodden and poor in their place by force (Amos 4:1; Mal 3:5; etc). In Israel, the justice of the Law (“You shall not oppress your neighbor,” Lev 19:13) was being ignored.
9 Ephraim is revealed to be the unjust merchant, “Canaan,” by his boast that he is rich and powerful. Thus his own testimony confirming his observed behavior becomes evidence against him in the lawsuit (cf. 8:2 and 10:3 for other examples of speech by the personified nation). His words are simple. They state his attitude of self-security. Ephraim rejoices in his wealth, with cofidence that it was worth the oppression of others, the immorality, the religious infidelity, and with confidence also that it made him a secure nation.
But it is worthless. The prophet, perhaps quoting the words of the divine prosecutor of the lawsuit, announces the folly of Ephraim’s misplaced trust. His “gains” (יגיעיו) will do him no good. How can they help him when he faces Yahweh’s wrath? Ephraim is doomed and doesn’t know it (cf. Amos 6:1–7; Zeph 1:11–13). He will not be able to buy his way out of the coming punishment; wealth will not “suffice” (מצא, niphal; curse type 15, futility). In gaining his obscene profits, Ephraim has “committed iniquity” (חטא … עון), i.e., shown himself to be a sinner. It is possible that assonance is to be noticed in the words מצא (twice), און / עון and לי / לו / לא as they are found in v 9a [8a] and 9b [8b] respectively, though this may be accidental rather than purposeful.
Douglas Stuart, vol. 31, Hosea–Jonah, Word Biblical Commentary (Dallas: Word, Incorporated, 2002), 192-93.
Garrett usefully explains that oppression and deceit will receive the judgment of God:
The rigged scales of the merchant are proverbial for loathsome dishonesty in trade.187 This kind of fraud, a way of cutting any corner to get ahead,188 is in the worst traditions of the Israelite merchant’s ancestor, Jacob.189 There is a wordplay linking v. 7 to v. 8. The word for “merchant” in v. 7 [Hb. 8] is kĕnaʿan, a word that also means “Canaan.” In v. 8 Hosea calls the prosperous merchant and upper classes “Ephraim.” The point is that the successful but unscrupulous mercantile class of Ephraim has become Canaan, that is, a people who are as unethical as the original Canaanites. These people believe that their wealth and connections have put them out of reach of prosecution; they have acquired the status of being above the law. The merchant’s assertion is not, “With all my wealth they will not find in me any iniquity or sin,” as in the NIV, but, “With all my wealth they will not find in me any iniquity for which I can be held accountable.” The point is that although they may escape retribution within the justice system of Israel, they will not escape Yahweh’s retribution.
Duane A. Garrett, vol. 19A, Hosea, Joel, The New American Commentary (Nashville: Broadman & Holman Publishers, 1997), 241-42.