Of note is that the sea symbolizes several things for the Jewish people in antiquity, most notably disaster or ruin. For the most part, the ancient Jews were not seafaring people. Deuteronomy 28:68 gives them a stern warning against disobedience, clearly stating that disobedience would ultimately lead to a re-enslavement with the notable inclusion of being sent back in ships ("And the LORD will bring you back in ships to Egypt, a journey that I promised that you should never make again; and there you shall offer yourselves for sale to your enemies as male and female slaves, but there will be no buyer.”)
The waters/sea are also present in the Deluge, the Exodus, Jonah's adventure, etc. The Psalmist also speaks of it with a fearful reverence in Psalm 107:23-32.
Other notable verses state:
"The wicked are like the troubled sea, when it cannot rest" (Isaiah 57:20).
"There is sorrow on the sea; it cannot be quiet" (Jeremiah 49:23).
Most appropriately to the topic at hand, though, is that the sea is also a symbol of complete and total separation, something which is notably present in the writings of John the Apostle in the book of Revelation, Ch. 21. In 21:1, you read "...the first heaven and the first earth had passed away, and there was no longer any sea." Now that's an interesting phrase. No longer any sea, John? Why would you make note of that?
John's peculiar circumstance led to the development of a particular disdain towards the sea, which the text clearly demonstrates. He was in exile on the Island of Patmos; twas a barren, empty island. Finding himself amid a proverbially damning sea, and cut off by its waves from all that which he loved best. How often do you think he would turn his gaze and helplessly look towards his own beloved land of Palestine? What wonder, then, that he would have constant thoughts and visions of making it home (that is, heaven), and in doing so, is it any wonder that he should say, "And there was no more sea"? For the sea, the dreaded sea, represented separation. And in crossing that chasm, John would finally find himself in heaven.
Thus, we see a clear source from which these writings and others may draw from when they present heaven, a place of joy and repose, found across that pesky, troublesome sea.