I believe he chose "heart of the earth" specifically to draw a parallel to a previous verse:
Mat 12:35 A good man out of the good treasure of the heart bringeth forth good things: and an evil man out of the evil treasure bringeth forth evil things.
I believe that part of the point he was making was that a good thing would come out of the heart of the earth after three days and three nights.
And though it's the only verse that says three days and three nights, it was spoken by Christ and it was confirmed that others heard it and understood it's meaning:
Mat 27:62 Now the next day, that followed the day of the preparation, the chief priests and Pharisees came together unto Pilate,
Mat 27:63 Saying, Sir, we remember that that deceiver said, while he was yet alive, After three days I will rise again.
Notice that this too confirms three days and three nights:
Jesus buried just before sunset wednesday - 1 night in grave
next day Thursday - 1 day in grave
next night thursday - 2 nights
next day friday - 2 days
next friday - 3 nights
next day saturday - 3 days
. The verse said that "After three days" he will rise again. This fits perfectly with Christ's sign.
I guess I can't quite see what you were driving at, but if I understand correctly are you saying you believe it to be a future prophecy of someone else?
Matthew 12
38 Then some of the Pharisees and teachers of the law said to him, "Teacher, we want to see a miraculous sign from you."
39 He answered, "A wicked and adulterous generation asks for a miraculous sign! But none will be given it except the sign of the prophet Jonah.
40 For as Jonah was three days and three nights in the belly of a huge fish, so the Son of Man will be three days and three nights in the heart of the earth.
Matthew 13: 1 That same day Jesus went out of the house and sat by the lake.
Later...
Matthew 15: 32 Jesus called his disciples to him and said, "I have compassion for these people; they have already been with me three days and have nothing to eat. I do not want to send them away hungry, or they may collapse on the way."
39 After Jesus had sent the crowd away, he got into the boat and went to the vicinity of Magadan.
The next day...
Matthew 16 1 The Pharisees and Sadducees came to Jesus and tested him by asking him to show them a sign from heaven.
2 He replied, "When evening comes, you say, `It will be fair weather, for the sky is red,´ 3 and in the morning, `Today it will be stormy, for the sky is red and overcast.´ You know how to interpret the appearance of the sky, but you cannot interpret the signs of the times.
4 A wicked and adulterous generation looks for a miraculous sign, but none will be given it except the sign of Jonah." Jesus then left them and went away.
We have the sign of Jonah, but no three days and three nights?? He had just fulfilled that part.
Now the sign of Jonah!
2 Kings 14:25 He was the one who restored the boundaries of Israel from Lebo Hamath to the Sea of the Arabah, in accordance with the word of the LORD, the God of Israel, spoken through his servant Jonah son of Amittai, the prophet from Gath Hepher.
The restored boundaries of Israel! 1967!
A big little war
In June, 1967, there was a short, violent war between Israel and the Arab nations, called the Six-Day War. Israel prevailed, and captured the old city of Jerusalem, along with other territory. This is significant especially because the Israeli recapture of Jerusalem ended the "times of the Gentiles" spoken of by the Prophets. Jerusalem had been under Gentile domination for more than 2,000 years. Then it became, once again, a Jewish city, and events prophesied in conjunction with that began to occur.
At about the same time another event took place, which is only now being noticed by most of the world, but which is also an important event: The modern Messianic Jewish movement became a reality about the time of the Six-Day War.
For the first time in over 1,500 years, Jews generally were free to come to faith in Yeshua as their Messiah, and remain Jews. For the first time, there are Jewish congregations who believe in Jesus, the Jewish Messiah. And, amazingly, non-Jews have joined these believing Jews in worshiping the God of Abraham, Isaac and Jacob in a Jewish manner: there are as many "Messianic believers" (non-Jewish believers who adopt a Jewish lifestyle) as there are Messianic Jews.
http://www.quodlibet.net/lbaden-messianic.shtml
Galilee, Sea of: ( Mat 4:18; 15:29), is mentioned in the Bible under three other names. ( 1.) In the Old Testament it is called the "sea of Chinnereth" ( Num 34:11; Jos 12:3; 13:27), as is supposed from its harp-like shape. ( 2). The "lake of Gennesareth" once by Luke ( Luk 5:1), from the flat district lying on its west coast. ( 3.) John ( Jhn 6:1; 21:1) calls it the "sea of Tiberias" ( q.v.). The modern Arabs retain this name, Bahr Tabariyeh.
This lake is 12 1/2 miles long, and from 4 to 7 1/2 broad. Its surface is 682 feet below the level of the Mediterranean. Its depth is from 80 to 160 feet. The Jordan enters it 10 1/2 miles below the southern extremity of the Huleh Lake, or about 26 1/2 miles from its source. In this distance of 26 1/2 miles there is a fall in the river of 1,682 feet, or of more than 60 feet to the mile. It is 27 miles east of the Mediterranean, and about 60 miles north-east of Jerusalem. It is of an oval shape, and abounds in fish.
Its present appearance is thus described: "The utter loneliness and absolute stillness of the scene are exceedingly impressive. It seems as if all nature had gone to rest, languishing under the scorching heat. How different it was in the days of our Lord! Then all was life and bustle along the shores; the cities and villages that thickly studded them resounded with the hum of a busy population; while from hill-side and corn-field came the cheerful cry of shepherd and ploughman. The lake, too, was dotted with dark fishing-boats and spangled with white sails. Now a mournful, solitary silence reigns over sea and shore. The cities are in ruins!" This sea is chiefly of interest as associated with the public ministry of our Lord. Capernaum, "his own city" ( Mat 9:1), stood on its shores. From among the fishermen who plied their calling on its waters he chose Peter and his brother Andrew, and James and John, to be disciples, and sent them forth to be "fishers of men" ( Mat 4:18,22; Mar 1:16-20; Luk 5:1-11). He stilled its tempest, saying to the storm that swept over it, "Peace, be still" ( Mat 8:23-27; Mar 7:31-35); and here also he showed himself after his resurrection to his disciples ( 21). Jhn 21).
"The Sea of Galilee is indeed the cradle of the gospel. The subterranean fires of nature prepared a lake basin, through which a river afterwards ran, keeping its waters always fresh. In this basin a vast quantity of shell-fish swarmed, and multiplied to such an extent that they formed the food of an extraordinary profusion of fish. The great variety and abundance of the fish in the lake attracted to its shores a larger and more varied population than existed elsewhere in Palestine, whereby this secluded district was brought into contact with all parts of the world. And this large and varied population, with access to all nations and countries, attracted the Lord Jesus, and induced him to make this spot the centre of his public ministry."
Psalm 49:4 I will incline mine ear to a parable: I will open my dark saying upon the harp.
harp
Hebrew for 03658 Kaf-Nun-Vav-Reish
Pronunciation Guide kinnowr {kin-nore'}
from a unused root meaning to twang
Outline of Biblical Usage
1) lyre, harp
AV - harp 42; 42
Hebrew for 03672 Kaf-Nun-Reish-Vav-Tav
Pronunciation Guide Kinn@rowth {kin-ner-oth'} or Kinnereth {kin-neh'-reth}
respectively pl. and sing. fem. from the same as 03658
Outline of Biblical Usage
Chinneroth or Cinneroth or Chinnereth = "harps"
1) the early name of the Sea of Galilee
2) a town and district in Naphtali near the Sea of Galilee
AV - Chinnereth 4, Chinneroth 2, Cinneroth 1