Marching into battle without divine support is a guaranteed path to failure. A reckless, independent military campaign proves that victory does not rely on human strength, but solely on the presence of God. The struggle for the land is not a conventional war; rather, it is a conflict where salvation belongs entirely to God [ביאור יש״ר]. Without miracles and divine assistance, the Israelites are simply unable to overcome the powerful nations standing against them [מלבי״ם]. Therefore, the declaration that God is not among them means His Divine Presence has been completely removed [נתינה לגר], making any attempt to fight utterly pointless [ביאור יש״ר].
The warning given to the people contains a deliberate double instruction, telling them neither to advance up the mountain nor to engage in battle. This raises a natural question, as avoiding the mountain would automatically prevent the battle [שפתי חכמים], and the physical act of climbing is not inherently wrong [משכיל לדוד]. The primary approach among commentators is that the instruction to halt their climb is not just a standard warning, but a statement of fact about their future. It serves as a stark reality check that this military campaign will not lead to their rise, but rather to a steep downfall [רש״י].
Some explain that the Israelites had already physically reached the mountaintop, prompting Moses to clarify that this physical climb would bring them no true elevation or success [משכיל לדוד]. Another perspective notes that Moses carefully selected his words because human speech has the power to shape reality. By stating they would not rise, he cemented the fact that their actions would lead only to a decline [גור אריה]. Ultimately, these harsh words were spoken purely for the benefit of the Israelites, meant to save them from an impending disaster [מזרחי, שפתי חכמים].
The final caution warns against a crushing and absolute defeat [ביאור שטיינזלץ]. Because the danger was so severe, the Israelites were ordered to avoid conflict entirely. Even if their enemies charged down the mountain to attack them, they were strictly forbidden from fighting back. Instead, their only option was to retreat immediately and travel back toward the desert [מלבי״ם].