Those who regard lying vanities forsake their own mercy.
Jonah could have composed the core of this psalm, which contains his prayer, while he was inside the great fish. He may have composed or polished the whole psalm sometime after he was safely back on dry land. It bears many similarities to other psalms in the Psalter. Clearly Jonah knew the psalms well, and he could have spent much time reflecting on them during his three days in the fish. One wonders, however, how anyone could think very coherently inside a fish.