Rashi on Deuteronomy 31:7/רש"י על דברים ל״א:ז׳

1כי אתה תבוא את העם הזה — Translate this as the Targum does: ארי אתה תעול עם עמא הדין, THOU SHALT GO WITH THIS PEOPLE. Moses, by the statement “Thou shall go with this people” (as one of them) said in effect to Joshua: The elders of the generation will be with thee: everything has to be done according to their opinion and their advice. The Holy One, blessed be He, however, said to Joshua, (v. 23) “For thou shalt bring (תביא) the children of Israel into the land which I swore unto them” — thou shalt bring them even against their will; everything depends on you alone: if necessary take a stick and beat them over the head: there can be but one leader for a generation, and not two leaders for a generation (Sanhedrin 8a).