We are told in the parsha that Yaakov give you Yosef the portion of Shechem in addition to his equal portion given to the brothers. This portion of Shechem was acquired through the Cherev and Keshes (sword and bow). Rashi tells us that the Cherev is Chochma (wisdom) and the Keshes is Tefillah (prayer) The Shem Mishmuel explains that, as a sword, Chochma needs to constantly be sharpened to remain an effective weapon and that, just as an arrow travels only as far as its bow is flexed, so too our Tefillah and spirituality will only take us as far as we are invested.