THIS book of Jonah, though it be placed here in the midst of the prophetical books of scripture, is yet rather a history than a prophecy; one line of prediction there is in it, Yet forty days, and Nineveh shall be overthrown; the rest of the book is a narrative of the preface to and the consequences of that prediction. In the midst of the obscure prophecies before and after this book, wherein are many things dark and hard to be understood, which are puzzling to the learned, and are strong meat for strong men, comes in this plain and pleasant story, which is entertaining to the weakest, and milk for babes. Probably Jonah was himself the penman of this book, and he, as Moses and other inspired penmen, records his own faults, which is an evidence that in these writings they designed God’s glory and not their own.
We read of this same Jonah 2 Kings xiv. 25, where we find that he was of Gath-hepher in Galilee, a city that belonged to the tribe of Zebulun, in a remote corner of the land of Israel; for the Spirit, which like the wind, blows where it listeth, will as easily find out Jonah in Galilee as Isaiah at Jerusalem. We find also that he was a messenger of mercy to Israel in the reign of Jeroboam the second; for the success of his arms, in the restoring of the coast of Israel, is said to be according to the word of the Lord which he spoke by the hand of his servant Jonah the prophet. Those prophecies were not committed to writing, but this against Nineveh was, chiefly for the sake of the story that depends upon it, and that is recorded chiefly for the sake of Christ, of whom Jonah was a type; it contains also very remarkable instances of human infirmity in Jonah, and of God’s mercy both in pardoning repenting sinners, witness Nineveh, and in bearing with repining saints, witness Jonah
– Matthew Henry Commentary