That Yehoshua's name was instrumental in distinguishing him and maintaining him true to our national mission is certainly intimated in the text. Yet exactly how his name helped is debated in the midrashim. Rashi quotes that Yehoshua's name carried his Rebbe's prayer that Hashem should save him from the counsel of his colleagues. It requires little imagination to appreciate the efficacy of any Rebbe's prayer and ever so more when Moshe Rabeinu is the Rebbe. However the medrash which tracks the new "yud" that was added to Hoshea to make him Yehoshua and finds one that has floated for several centuries, ever since it was dropped from Sarah our Matriarch, does require comment. True, Sarah was Sarai and she lost her '"yud" presumably, to mark her ascension to universal contribution and recognition, just as the "heh" did for Avraham. Yet her connection to Yehoshua and the mission of the meraglim and how that would give direction to Yehoshua, is not at all clear.
Addressing this question, Harav Nisan Alpert zt"l suggests that Yehoshua's mission both as a spy and ultimately as the conqueror of Eretz Yisrael would forever have to be informed with the passion of Sara's commitment to our land. Sarah made the painful and forever unpopular demand of her husband to send Yishmael away "as he cannot inherit together with my son Yitzchak". It was Sarah, a matriarch looking far into the future, who first expressed with resolve and clarity that Yitzchak and Yishamel could not be partners in Israel. Unfortunately it is no longer surprising that it would take the understanding of a mother and the insight of a prophetess to unabashedly establish for us our singular relationship to our land. Indeed Avraham in his "eishes chayil" eulogy for Sarah recognizes for "having sought wool and linen", as if to say she understood that which would contribute fully, only when left undiluted by combination.
Undoubtedly the passion of Sarah will drive Yehoshua the general to push the conquest with might and vigor, but how will it make a difference for Yehoshua the scout? How will this yud borrowed from Sarah strengthen him to withstand the pressure of colleagues with a vastly different perception?
Perhaps it is not coincidental that it is the small yud which connects Yehoshua to Sarah's vision. The role of the "yud" in Hebrew, as we all know from our youth, is that it connotes personal possession. Shulchan refers to any table; shulchani is my table; eretz is any land and artzi is my land. Thus Moshe was reminding Yehoshua that he must view the land as his very own and in that which is yours you will see only good. This is reminiscent of one of life's truths formulated in the Talmud as "chen hamakom al yoshveho". Loosely translated, this means that whatever you call home will hold a charm for you that will often leave others totally mystified. It is true about our hometown; it is true about our homes and backyards; it most certainly is true for all that we have come to call home. Indeed possession is nine tenths of perception.