On the face of it, the narrative is not meant to be strictly historical. Its place among the prophetic books shows that its importance lies, not in its facts, but in the truths for which it pleads. Much detail is wanting which we should expect to find were the narrative pure history, e.g. the name of the Assyrian king, the results of Jonah's mission, etc. Other circumstances stamp it as unhistorical: considering the poor success the Hebrew prophets had in their own land, such a wholesale conversion of a foreign city, even if such a visit as Jonah's were likely, must be regarded as extremely improbable, to say nothing of the impossibility of the animals fasting and wearing sackcloth, iii.7, 8. The miraculous fish and the miraculous tree which grew up in a single night forbid us to look for history in the book. Nineveh's fame is a thing of the past, iii.3; the book is written after, probably long after, its fall in 606 B.C. The lateness of the book and its remoteness from the events it records, are proved in other ways. Its language has the Aramaic flavour of the later books, and such a phrase as "the God of heaven," i.9, only occurs in post-exilic literature. It contains several reminiscences of late books (e.g. Joel?), and its ideas are most intelligible as the product of post-exilic times, especially if it be regarded as a protest against a loveless and narrow-hearted type of Judaism. All the conditions point to a date not much, if at all, earlier than 300 B.C.
Jonah is himself a historical character; there is no reason to doubt that the prophet, in whose time Nineveh is standing, i.2, is contemporary with the Jonah mentioned in 2 Kings xiv.25 as living in the reign of Jeroboam II, and prophesying the restoration of Israel to its ancient boundaries. It may have been as the representative of an intense and exclusive nationalism that he was chosen as the hero of this book. Here and there the story trenches on Babylonian and Greek legend, but the spirit, if not also the form, is altogether the author's own.
The book abounds in religious suggestion; even its incidental touches are illuminating. It suggests that man cannot escape his divinely appointed destiny, and that God's will must be done. It suggests that prophecy is conditional; a threatened destruction can be averted by repentance. It is peculiarly interesting to find so generous an attitude towards the religious susceptibilities and capacities of foreigners: in this we are reminded of Jesus' parable of the good Samaritan. The foreign sailors cry, in their perplexity, to their gods, and end by acknowledging the God of Israel; the people of Nineveh repent at the prophet's preaching. All this forms a splendid foil to the smallness and obstinacy of Jonah. With his mean views of God, he would not only exclude the heathen from the divine mercy, but rejoice in their destruction. In this the prophet is typical of later Judaism, with its longing for the annihilation of the nations as the obverse of the redemption of Zion. This attitude was greatly encouraged by the rigorous legislation of Ezra; and Jonah, like Ruth, may be a protest against it, or at least against the bigotry which it engendered. If Israel is, in any sense, an elect people, she is but elected to carry the message of repentance to the heathen; and the book of Jonah is indirectly, though not perhaps in the intention of the author, a plea for foreign missions.
The greatest lesson of the book is skilfully reserved to the end, iv, 2, 10, 11. It is that God is patient and merciful, that He loves all the world which He created, that His love stretches not only beyond the Jews and away to distant Nineveh, but even down to the animal creation. He hears the prayer of the foreign sailors, He delights in the repentance of Nineveh, He cares for the cattle, iv.11. This book is the Old Testament counterpart to "God so loved the world."