"And God said unto Avrohom: Sarai your wife shall no longer be called by the name 'Sarai', for 'Sarah' shall be her name." (Bereshis 17:15) The Torah Temimah in Parshas Shelach (Bamidbar 13:16) quotes a well-known Talmud Yerushalmi which indicates that the letter yud of Sarah's former name was transferred to form the beginning of Yehoshua's name, altering it from Hoshea to Yehoshua. What is the meaning of this aggadic explanation?

Targum Yonasan ben Uziel (ibid.) seemingly interprets Moshe's renaming of Yehoshua as a prayer for Yehoshua to be courageous in the face of adversity. The Targum states, "When Moshe saw the meekness of Hoshea bin Nun, he he called his Yehoshua." In other words, Moshe was concerned that the humble Hoshea would not be able to be defiant in the face of a possibly rebellious gangmanship of meraglim. He thus prayed that God endow Hoshea with the courage to stand his ground and confront his comrades with full vigor and valor, should the need arise. (This tefilla for courage is likely the basis of the oft-repeated phrase "Chazak ve'ematz", which was used in particular reference to Yehoshua in the Torah and throughout Sefer Yehoshua.)

Keli Yakar (on Bereshis 21:10) posits that Sarah insisted on the expulsion of Yishmael from Avrohom Avinu's household due to the adverse influence which Yishmael would have on Yitzchak. Although Sarah's request would seem to a naive observer to be harsh and inhumane, God endorsed her words (ibid. pasuk 12).

It is clear that Sarah "had the guts" and boldness to stand up for what was right and go against the perceived norm, even in the face of intense pressure. It is precisely this middah of "gevurah" (boldness) which Moshe prayed would be instilled in the humble Hoshea bin Nun. The transfer of the letter yud from Sarai to Yehoshua represents the endowing of Yehoshua with Sarah's boldness for the sake of Heaven. May we merit to exemplify such gevurah when called upon.