Was Jonah truly swallowed by a whale?

How could Jonah survive three days in the belly of a great fish

Jonah 1:17 Now the LORD had prepared a great fish to swallow up Jonah. And Jonah was in the belly of the fish three days and three nights.

Matthew 12:40 For as Jonas was three days and three nights in the whale's belly; so shall the Son of man be three days and three nights in the heart of the earth.

Jonah son of Amittai appears in 2 Kings as a prophet from Gath-hepher (a few miles north of Nazareth) active during the reign of Jeroboam II (c.786-746 BC), where he predicts that Jeroboam will recover certain lost territories.

For many, the supernatural events recorded in the Bible seem too impossible to be true.

In the book of Jonah the Hebrew word for the sea creature is דג dag, meaning ‘fish’. In the New Testament, the Greek word used by Matthew was κήτος kētos, meaning ‘sea monster’, and is so rendered in the Revised Version margin. The King James Version translators translated this term as ‘whale’, possibly because it was the largest sea creature of which they knew. What the text says is that ‘God had prepared a great fish to swallow Jonah’ (Jonah 1:17). 

The words imply either a special act of creation, or of modification of an existing sea creature to accommodate Jonah safely. Jonah prayed to God ‘out of the fish’s belly’ (Jonah 2:1). ‘Belly’ is a fairly vague term in English, let alone in ancient Hebrew, so if Jonah was swallowed by a creature such as a sperm whale, he might have been in the great laryngeal pouch; if by a shark, he may have been in the stomach of a creature specially prepared by God to protect him from the effects of its gastric juices.

Jonah is miraculously saved by being swallowed by a large fish specially prepared by God where he spends three days and three nights. In chapter two, while in the great fish, Jonah prays to God in his affliction and commits to thanksgiving and to paying what he has vowed. God commands the fish to spew Jonah out.

God again orders Jonah to visit Nineveh and to prophesy to its inhabitants. This time he goes and enters the city crying, "In forty days Nineveh shall be overthrown." After Jonah has walked for a day across Nineveh, the people of Nineveh begin to believe his word and proclaim a fast. 

The king of Nineveh puts on sackcloth and sits in ashes, making a proclamation to decree fasting, sackcloth, prayer, and repentance. God sees their works and spares the city at that time. The entire city is humbled and broken with the people (and even the animals) in sackcloth and ashes. Animals, plants, warmth and even fish are all seen under the sovereign hand of God. Even the king comes off his throne to repent.

Displeased by this, Jonah refers to his earlier flight to Tarshish while asserting that, since God is merciful, it was inevitable that God would turn from the threatened calamities. He then leaves the city and makes himself a shelter, waiting to see whether or not the city will be destroyed.

God causes a plant (in Hebrew a Kikayon) to grow over Jonah's shelter to give him some shade from the sun. Later, God causes a worm to bite the plant's root and it withers. Jonah, now being exposed to the full force of the sun, becomes faint and desires that God take him out of the world.

And God said to Jonah: 'Art thou greatly angry for the Kikayon?' And he said: 'I am greatly angry, even unto death.'

And the LORD said: 'Thou hast had pity on the gourd, for which thou hast not labored, neither maddest it grow, which came up in a night, and perished in a night;

and should not I have pity on Nineveh, that great city, wherein are more than six score thousand persons that cannot discern between their right hand and their left hand, and also much cattle?'