Albert Barnes Commentary Jonah 2:8

"They that regard lying vanities Forsake their own mercy." — Jonah 2:8 (ASV)

Those who observe lying vanities – that is, those who (reflecting the force of the Hebrew form for "observe") diligently watch, pay deference to, court, or sue "vanities of vanities"—vain things, which prove themselves vain at last, failing the hopes that trust in them. Such were actual idols, in which people openly professed that they trusted. Such are all things in which people trust, apart from God. One is not more vain than another. All have this common principle of vanity: that people look, apart from God, to that which has its only existence or permanence from God.

It is then one general maxim, including all people’s idols: idols of the flesh, idols of intellect, idols of ambition, idols of pride, idols of self and self-will. People "observe" them as gods, watch them, hang upon them, never lose sight of them, and guard them as if they could keep them.

But what are they? "Lying vanities," breath and wind, which no one can grasp or detain, vanishing like air into air.

And what do those who so "observe" them do? All alike "forsake their own mercy;" that is, God, "Whose property is always to have mercy," and who would be mercy to them, if they would. So David calls God my mercy (Psalms 144:2). Abraham’s servant and Naomi praise God that He has not forsaken His mercy (Genesis 24:27; Ruth 2:20).

Jonah does not, in this, exclude himself. His own idol had been his false love for his country: he would not have his people go into captivity when God willed; he would not have Nineveh preserved, the enemy of his country. By leaving his office, he left his God, "forsook" his "own mercy." See how God speaks of Himself as wholly belonging to those who are His. He calls Himself "their own mercy."

He does not say, "those who" do "vanities" (for, as Ecclesiastes 1:2 says: ‘vanity of vanities, and all things are vanity’), lest he seem to condemn all and to deny mercy to the whole human race. Instead, he speaks of "those who observe, guard vanities," or lies; "they," into the affections of whose hearts those "vanities" have entered; who not only "do vanities" but who "guard" them, loving them, deeming that they have found a treasure—these "forsake their own mercy."

Although mercy may be offended (and by mercy we may understand God Himself, for God is, as stated in Psalm 145:8, "gracious and full of compassion; slow to anger and of great mercy"), yet He does not "forsake," does not abhor, "those who guard vanities," but awaits their return. These, on the contrary, of their own will, "forsake mercy" standing and offering itself.