The impending victory over Sihon, king of the Amorites, reveals a fascinating dynamic between divine providence, spiritual reality, and military tactics. While the upcoming conflict initially appeared to be the result of a failed diplomatic negotiation, it becomes clear that this was a deliberate, planned move by God [ברכת אשר על התורה].
God informs Moses that the defeat of the Amorite king has already taken place, even before the actual battle begins. One approach explains this early victory on a spiritual level. God speaks to Moses personally, revealing a hidden spiritual reality that only someone of his greatness could perceive. The downfall of any mortal king first requires the defeat of his spiritual guardian in heaven. God showed Moses exactly how He had already subdued the spiritual prince of the Amorites, trampling him underfoot [רש״י, אלשיך, ברכת אשר על התורה]. In this light, the early victory also carries a sense of physical weakness; God let Moses know that He had already weakened Sihon's power and forced him into submission [ברטנורא על התורה].
A second approach explains this early victory in practical and strategic terms. Sihon's downfall actually started the moment God hardened his heart, causing him to reject the Israelites' peace offer [אור החיים, ביאור יש״ר, רש ר הירש]. From a military standpoint, the victory was set in motion when Sihon chose to march out with his entire nation to confront the Israelites. By taking the offensive, he abandoned his fortified cities, leaving them completely without a defense [מלבי״ם]. This victory stands as an open miracle. The Israelites were not trained in warfare and were physically weak from a lack of bread and wine, yet God delivered this mighty king directly into their hands [צרור המור].
Beyond the initiation of the war, God's declaration also indicates that He made Sihon's territory secular, removing its protected status and making it legally permitted for conquest. This holds deep historical and legal significance. Originally, the land of Sihon and his capital city belonged to the nations of Ammon and Moab, which the Israelites were strictly forbidden from attacking. However, because Sihon had previously conquered these areas from them, the territory was cleared of its protected status and became entirely permissible for the Israelites to capture [תורה תמימה על התורה, צפנת פענח].
Finally, the command to take the land carries a dual instruction: to expel and to inherit. God commands Moses to drive Sihon out of his territory so that the Israelites can take full possession of it [העמק דבר]. Through this, God instructs Moses to launch the broader campaign of conquering and inheriting the entire land, starting specifically with Sihon's territory [רש ר הירש]. He is told to carry out this mission with absolute confidence, strength, and without a single moment of hesitation [ביאור שטיינזלץ].