Bamidbar 15:38
דַּבֵּר אֶל בְּנֵי יִשְׂרָאֵל וְאָמַרְתָּ אֲלֵהֶם וְעָשׂוּ לָהֶם צִיצִת עַל כַּנְפֵי בִגְדֵיהֶם לְדֹרֹתָם וְנָתְנוּ עַל צִיצִת הַכָּנָף פְּתִיל תְּכֵלֶת

Each corner of our garment should include a thread of techeiles.
Chazal teach us that this thread serves as an inspirational reminder. The color of techeiles resembles the color of the sea floor, the color of the sea floor is similar to the color of shamayim, and the color of the shamayim is similar to the color of Hashem’s throne of glory – the Kisei HaKavod. By gazing at the techeiles thread we begin a process that ends in being reminded of Hashem’s throne of glory.
 
Rashi in Bava Metzia 61b, notes that there are two ways to produce the color/appearance of techeiles. The halachically correct way is to extract the dye from a sea creature called the Chilazon. According to Menachos 44a, this Chilazon is a rare sea creature that appears on land only once in 70 years. Because the Chilazon emerges so infrequently, the dye produced from the Chilazon is less accessible and very expensive.
The halachically invalid way of producing the desired color is through an extract of the indigo plant. Since the indigo plant is commonly found, the dye produced from it is relatively inexpensive. The Gemara warns that Hashem will punish anyone who hangs wool dyed with the extract of the indigo on his garment claiming that he possesses techeiles.

Rav Aharon Lewin ztl, asks the following question:
If chazal teach us that the reason we have a thread of techeiles is so that we gaze at its color and be inspired to remember Hashem’s throne, what difference does it make as to the origin of this color? As long as we have the correct color, it will remind us of Hashem’s throne. The end result from either approach is the same!

The answer, of course, is that there are 2 ways to produce the color of techeiles: the hard way and the easy way.
The hard way involves waiting up to 70 years for the chilazon to appear, and carefully extracting a rare dye. The easy way is to obtain the color from a commonly found vegetable plant.
When we perform a mitzvah commanded to us by Hashem, it is as if we are appearing before the throne of Hashem and presenting Him with a gift. When one performs a mitzvah without any thought or preparation, simply to check a box, it is as if he took a shortcut to appear before Hashem; he has come before Hashem with indigo. However, when one dedicates the time and invests the necessary preparation to perform a mitzvah fully and correctly, it is if he took a long, arduous road to come before Hashem; he has come before Hashem with techeiles.

When we look at the techeiles we are reminded not just of our destination to Hashem’s throne but of the journey as well. Just as one waits with great anticipation for 70 years for the chilazon to appear and appreciates its great value, likewise we are reminded that we must approach the performance of mitzvos with anticipation and appreciate what it means to have an opportunity to perform a mitzvah, and in its proper fashion.

The difference between techeiles and indigo teaches us that it is not only the destination that counts but the journey as well. 

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A quick idea on Yehoshua’s name change: The midrash says that when Hashem changed Sarai’s name to Sarah, He allocated the displaced yud for Yehoshua’s name, from Hoshea. Rav Nison Alpert notes that Sarah paved a very important path for Yehoshua. Sarah had the unequivocal belief that Eretz Yisrael – in its entirety – belongs to the children of Avraham and Yitzchak. In Breishis 21:10 she says:
גָּרֵשׁ הָאָמָה הַזֹּאת וְאֶת-בְּנָהּ כִּי לֹא יִירַשׁ בֶּן-הָאָמָה הַזֹּאת עִם-בְּנִי עִם-יִצְחָק 

Sarah was saying that Yishmael, the son of Haggar, has no share in the inheritance of her son Yitzchak. Yishmael, nor any descendant of his has a portion in Eretz Yisrael. With great passion, Sarah conveyed this message to Avraham, and Hashem backed it up by saying:
כֹּל אֲשֶׁר תֹּאמַר אֵלֶיךָ שָׂרָה שְׁמַע בְּקֹלָהּ 

Yehoshua, who was chosen by Hashem to lead Bnei Yisrael into Eretz Yisrael and conquer the land, receives part of his name from Sarah, precisely because of her conviction on this matter. Equipped with a “piece” of Sarah, so to speak, Yehoshua boldly leads Bnei Yisrael into the Promised Land, conquering every corner of the land. B’ezras Hashem, hopefully the day when all of Eretz Yisrael is peacefully in our hands, is rapidly approaching.