Jonah 2:8 [HB 2:9] is a tricky verse to understand because of its ambiguity. The 2011 NIV translates this verse as those who cling to worthless idols turn away from God’s love for them. Literally, the verse reads those who give regard to worthless vanities forsake their mercy (משמרים הבלי שוא חסדם יעזבו). The KJV translates this verse fairly literally as they that observe lying vanities forsake their own mercy. The English translations either effectively follow the KJV using the phrase their own mercy for חסדם (their mercy), which retains something of the ambiguity of the original Hebrew, or else they take the third person plural pronoun in חסדם objectively to mean the mercy that God could show to them. Apart from the NIV, the NLT, ESV, and ISV opt for this second approach.
Jonah 2:8 is actually ambiguous for two reasons: Is the phrase they who give regard to worthless vanities inclusive of Jonah; and is the phrase their mercy subjective or objective?
Regarding the first element of potential ambiguity, the phrase they who give regard to worthless vanities could be either inclusive or exclusive of Jonah. Does Jonah have in mind other people (perhaps even non-Israelites) who were idol worshipers, or does he see also himself (in his previously disobedient state) numbered among such idolaters?
Even though Jonah did not physically bow down to any idols, the key reason for Jonah running away from God lies in the fact that he did not want God’s mercy to be shown to the Ninevites. Jonah preferred a God who was not so merciful. And by having this preference, he had set up for himself a god of his own imagination. In addition, it makes sense in the wider context of Jonah showing some degree of repentance in Jon 2 to understand him in Jon 2:8 as including his disobedient self within the set of those who were worshiping worthless idols. It is as if he were saying: “If I had not turned back to God, then I would not have experienced his saving mercy.” It makes sense, therefore, to take the phrase they who give regard to worthless vanities as being inclusive of Jonah’s disobedient self, which contrasts in Jon 2:9 with his obedient self, who is dedicated to worshiping God appropriately.
The second element of ambiguity in Jon 2:8 has to do with the phrase their mercy. Is the third person pronoun in this phrase subjective (i.e., the phrase indicates the mercy that people are supposed to show to others, or perhaps even the faithfulness that people are supposed to show to God), or is it objective (i.e., the phrase indicates the mercy that people might be able to experience from God)? Is Jonah’s overall idea in Jon 2:8 the idea that idolatry causes people to forfeit God’s grace, or is it the idea that idolatry makes people less merciful to others or perhaps less faithful to God?
In the context, the main idea on the lips of Jonah is probably the idea that idolatry means that people will not get to experience God’s mercy, based on the understanding that the practice of idolatry leads to judgment. In the mind of Jonah, he was probably implying that it was a good thing that he had repented of his idolatrous and false thinking about God, because such repentance led to him experiencing God’s mercy.
However, even if it makes more sense in the context to understand the pronoun in question as being objective on the lips of Jonah, the subjective understanding is probably lurking in the background in the mind of the narrator. This can be seen from the thematic prominence of חסד in Jonah 3–4. The issue in chs. 3–4 is Jonah’s lack of mercy to the people of Nineveh, and his anger at God for showing mercy to them. Jonah might have repented of his false view of God when facing death in the middle of the ocean, but in reality his words in Jon 2:8 will end up condemning him for his own lack of mercy toward the Ninevites.
It is significant in this regard that God is described in the Old Testament as being a God who does not forsake his mercy (see Gen 24:27; Ruth 2:20; Ezra 9:9). Yahweh is merciful and compassionate. His character stands in great contrast to the character of Jonah that is revealed in Jon 3–4. Jonah will forsake his mercy. He chooses not to show compassion. This lack of compassion means that the god that he really worships is an idol. Jonah’s preferred god is a god who is different from the compassionate and merciful God revealed in the Scriptures. The ambiguity of the phrase חסדם, therefore, is seemingly deliberate.