Jonah 2:2

‘And he said,

“I called by reason of my affliction to YHWH,

And he answered me,

Out of the belly of Sheol I cried,

You heard my voice.”

As he sank into the sea after being hurled from the deck Jonah had felt that he was sinking into the belly of Sheol (the grave). He had felt that he was about to die. But he had cried to YHWH in his affliction and he now knew that YHWH had heard his voice and answered him, for here he was alive and able to pray and offer thanks.

For the thought of someone being in the belly of Sheol see Isaiah 5:14, ‘Sheol has enlarged herself and opened her mouth without measure, and their glory, and their plenty, and their pomp, and the one who rejoices among them will descend into it'. But in Jonah's case his meaning is brought out in Jonah 2:3. His experience was like being in the belly of Sheol because he was engulfed in water. Compare Psalms 18:5, ‘the cords of Sheol were round about me, the snares of death came on me.'