Commentary for Jonah 1:3

to flee to Tarshish—I.e, to a sea named Tarshish, which is outside the Holy Land. He said, “I will flee to the sea, for the Shechinah does not rest outside the Holy Land.” Said the Holy One, blessed be He, to him, “By your life, I have messengers like you to send after you and fetch you from there.” This is illustrated by an allegory of a priest’s slave who fled from his master and entered a cemetery [making it impossible for his master to retrieve him]. His master said to him, “I have slaves like you to send after you and fetch you from there.” Now what did Jonah see that he did not wish to go to Nineveh? He said, “The gentiles are quick to repent. Should I prophesy to them and they repent, I will be found condemning Israel, who do not heed the words of the prophets.” [from Mechilta, Exodus 12:1]

The Questions: Why did Jonah flee to Tarshish? If [he fled] so that the word of Hashem would not reach him, then, behold, Hashem had already commanded him [to go to Nineveh] and he refused to go on the mission. What difference does it make if he refuses once or if he refuses twice? And why did he flee to the sea and not to the desert and from there to chutz la’aretz [‘outside the Holy Land’]? For, behold, the sea is suitable for prophecy, as it is written that God appeared to Ezekiel in chutz la’aretz because he was in a place of water (Ezekiel 1:3). And the phrase ‘ba’ah Tarshish,’ ‘arriving Tarshish,’ [appears] incorrect, for it should have said, 'holechet Tarshish,' ‘going [to] Tarshish.’

Jonah went and fled toward Tarshish from before God: How could he flee?...The prophet was full of wisdom and intelligence; how could he think that he could flee from God? Rather, he sought to flee from before God; that is, from being in God's presence, which is the spirit of prophecy. He thought that if he were to leave the Land of Israel, the spirit of prophecy would no longer rest upon him. And so he would be able to refuse to go on the mission, since he thought that gentiles are quick to repent, and if he went to them on this mission of God, they would repent from their evil ways. And this would condemn Israel, since Jonah and the other prophets keep going to them on missions from God and they do not repent from their evil way....

He went and fled to Jaffa: The gaon said that Tarshish is Tarsus. But Rabbi Mevaser says that it is Tunis in Africa.

and he paid its hire—He paid its hire in advance; although it is not customary for those embarking upon the sea to pay the hire of the ship until they leave, he paid in advance. [Pirk&d’Rabbi Eliezer, ch. 10; Tanhuma, Vayikra 8].