דברים, פרק ג׳, פסוק כ״א

As the era of Moses draws to a close and the Israelites prepare to enter Canaan, the mantle of leadership shifts to Joshua. Moses prepares his young successor for the complex task of conquest by using recent victories as a psychological and spiritual anchor. He commands Joshua to remain strong and fearless in the face of the nations ahead [אור החיים, ביאור יש״ר]. This moment of encouragement is seen by some as the official transfer of power, marked by Moses laying his hands upon Joshua [חזקוני].

The exact timing of this encouragement is highly significant, occurring just as the eastern lands were being divided among the tribes of Gad and Reuben. This division caused Joshua deep anxiety, as he worried these tribes might abandon their devotion to God once separated from the rest of the nation [העמק דבר]. Furthermore, because Moses required the warriors of Gad and Reuben to serve as the vanguard in the upcoming battles, there was a risk that Joshua might attribute future success to their military prowess. To prevent this, Moses emphasizes at this precise moment that God alone is the true warrior, not human soldiers [אור החיים].

This message of confidence was not meant for Joshua alone. Moses instructed him to continually share this reassurance with the entire Israelite camp, uprooting any fear of the numerous and densely populated kingdoms awaiting them across the Jordan [אור החיים, חומת אנך, ביאור שטיינזלץ]. To cement this trust, Moses appeals to Joshua's firsthand experience, reminding him of the supernatural defeat of Sihon and Og [ביאור יש״ר]. These kings were formidable adversaries, considered even more powerful than Pharaoh and his army [רבנו בחיי, שפתי כהן]. God orchestrated their downfall not merely to capture territory, but as a psychological weapon to strike terror into the Canaanite nations, effectively weakening their resolve before the Israelites even crossed the river [מלבי״ם].

The magnitude of this miraculous victory was so profound that the Israelites ought to have sung a song of thanksgiving to God, just as they did after the splitting of the Red Sea. However, because these events took place in the fortieth year of their journey, closely coinciding with the impending death of Moses, the nation was consumed by deep sadness and could not bring themselves to sing. Consequently, the song of praise for the defeat of Sihon and Og was left unsung until it was completed generations later by King David in the Book of Psalms [רבנו בחיי, שפתי כהן].

Moses concludes by comforting Joshua, who must soon lead the people into the new land without his mentor. He promises that the triumphs of the past will repeat themselves on the western side of the Jordan [רבנו בחיי, ביאור שטיינזלץ]. Just as all twelve tribes united to defeat the eastern kings, they will remain united for the battles ahead [אור החיים]. A profound miraculous parallel bridges the leadership of the two men. Just as the sun would eventually stand still for Joshua in the Ayalon Valley, a similar miracle of the sun stopping had already occurred for Moses during his battle against Sihon [חומת אנך].