We sometimes think that salvation is about us doing what we can and God meeting us halfway. But Jonah’s rescue from the depths of the sea is a picture of how we are rescued from sin & death: Jonah’s contribution is to sink in utter helplessness with nothing of his own to offer … God’s contribution is to graciously and powerfully accomplish his salvation. Jonah’s prayer in chapter 2 expresses his thankfulness for God’s gracious salvation. But, read in light of chapter 4, it is a prayer that reflects his hypocrisy (since he is glad when he receives grace, but not when “those people” do) and pride (since he feels he deserves God’s grace while “those people” don’t).