In the verse, "[Sing] His praise from the end of the earth, those who go down to the sea" (Yeshaya 42:10), Yeshaya emphasizes that at the time of the future redemption, G-d's praise will be of such great force that it will extend beyond the normal population centers, and will include also the most remote places. Even though there are not many people in these places, and therefore one would expect that the news of the redemption, G-d's Word, and faith in Him should not reach there – His praise will be said there also. The poetic section begins with the heading: "Sing to Hashem a new song, His praise from the end of the earth." (ibid.) Yeshaya continues on to specify and illustrate the corners of the Earth where the news of G-d's praise will reach: "Those who go down to the seas and those that fill it, the islands and their inhabitants. The wilderness and its cities ... the open cities where Kedar dwells [in the desert – Radak]; those who dwell on bedrock ... They will render glory to Hashem, and relate His praise in the islands." (42:10-12)

Yeshaya opens the list of remote places that will also accept G-d's reign at the time of redemption with "those who go down to the seas," and he ends the list with the praise of the inhabitants of "the islands." What is special about the sea and the inhabitants of its islands, that Yeshaya finds something extra in the fact that they also will give honor to Hashem and say His praise?

This world was created because of Hashem's desire that His honor should be recognized also in the lower realms, in the lowly material world. However, even in our world there are varying levels in the Revelation of His honor. This is the meaning of the Mishna, "There are ten levels of holiness" (Kelim 1:6), which lists areas and places in an ascending level of holiness. The Mishna speaks only of the levels of holiness in Eretz Yisrael, since only there is there a halachic difference to the levels of holiness. Everywhere outside of Israel is on the level of "impurity of eretz ha'amim," but even there different levels exist. The lowest place, where it is possible to think that is no revelation of G-d's glory there – is the sea.

The basis for this is an analysis of Sefer Yona. Yona seeks to run away from before Hashem. Radak comments: "How could he run away? David said, "Where can I run away from You?' Rather, 'from before Hashem' is not like, 'from Hashem,' for the prophet [Yona] was full of wisdom and knowledge, and how could he think to run away from Hashem? Rather, 'from before Hashem' – from something that is before Hashem; i.e., the prophetic spirit. He thought that if he leaves Eretz Yisrael to outside of Israel, the prophetic spirit will not dwell on him." However, Yona does not just run away to outside of Israel. He runs far away to Tarshish, and this is not distance of location but distance of holiness. Yona does not distance from G-d geographically [since, "Where can I run away from you"], but rather he distances spiritually. Yona runs away to the sea, where G-d's Presence is least clearly seen of all places on earth.

Thus, the Targum explains that Tarshish does not denote a certain geographic location, but translates "coming to Tashish – going to the sea," meaning that Yona simply fled to the sea, [unlike Rashi, who explained 'Tarshish' as the name of a certain sea.] This is also explained in Pirkei D'Rebbi Eliezer (ch. 10): "I am running away to a place where His glory is not mentioned there. If it says about the sky that His glory is there, as it says, "Above the heavens is His glory" (Tehillim 113:4); if it says about the land that His glory is there, as it says, "The whole land is full of his glory" (Yeshaya 6:3) – I will run to a place where his honor is not mentioned there."

Why is the sea considered a place that His glory is not there? Does the verse, "The whole land is full of his glory" really come, Heaven forbid, to exclude places that are not really 'land,' such as the sea? We find that "The heavens declare the glory of G-d, and the firmament tells of His handiwork." (Tehillim 19:2) Clearly, "The whole land is full of his glory" come to emphasize that Hashem's honor is not only in the heavens, and not only "in His Temple all will proclaim, 'Glory!'" – but even this lowly world, in which He appears in a hidden manner, there also is His glory.

Rav Hutner (Pachad Yitzchak, Pesach #1) explains in this way Chazal's comment, "The patriarchs are the carriage for the Divine Presence." (Bereishit Rabbah 47:8) Generally, travel minimizes honor (cf. Rashi Bereishit 12:2), but there is a way that actually increases honor, and that is the travel of one who travels in a carriage. "The importance of a carriage is in that it serves as a sign of honor for the one who rides in it, even if he is traveling around." Thus, the very same reason that usually serves to minimize honor, serves in a carriage as a reason to increase honor. Before the patriarchs came, Hashem's reign was recognized only in the upper realms; once the patriarchs came, his honor was recognized also in this material world.

Based on this we can understand the significance of the sea. Man, and the place of his inhabitance, is the reason for adding to G-d's glory also on the land, since once man was created, G-d was called King also over the earth. Since the sea is not an inhabited place, and of all the places of the world it is least fit for living, there is room to think that His glory is not there. [This is also why the desert is mentioned in the verse, because the desert is also not fit for habitation, although more so that the sea.] Therefore, of all the creatures of Bereishit only the taninim, kings of the sea, are mentioned in the portion of Creation, to teach that His rule reigns also over them. [Livyatan has the gematriya of malchut, and the Chassidic works emphasize in this context the succah of the livyatan's skin.] Therefore, Yeshaya emphasizes that in the future the song of G-d's praise will be sung also by those who go down to the sea and live in the islands, because in the time of the redemption G-d will be King over the entire world, and His reign rules over everything – including the sea.