As the Israelites near the Promised Land, God establishes clear moral and geographic boundaries regarding neighboring nations. They receive a strict warning as they draw close to the Ammonite territory [אבן עזרא, ביאור יש״ר]. This approach, however, is only in the general direction of Ammon, as the Israelites do not reach the actual border, which lies east of Og's kingdom [העמק דבר, חזקוני]. God commands the Israelites not to lay siege to the Ammonites, provoke them in battle, or attempt to cross their land by force [ביאור שטיינזלץ, העמק דבר].
A subtle but significant distinction exists between the restrictions placed on the Israelites regarding Ammon compared to a previous warning about Moab. While the Israelites were only forbidden from provoking Moab into open conflict, the restriction regarding Ammon is absolute, forbidding provocation of any kind. One perspective suggests this is because the Ammonites were less hostile than the Moabites. Although neither nation offered the Israelites food or water, the Ammonites did not hire Balaam to curse them, nor did they use their daughters to lead the Israelites into immorality. This more restrained behavior is attributed to their ancestry, as their matriarch, Lot's younger daughter, acted with greater modesty than her older sister [כלי יקר]. Another approach explains the absolute ban on provocation practically and geographically. Because the Israelite camp was not passing directly along the Ammonite border, there was no risk of minor, localized skirmishes. Therefore, any provocation at all would inevitably escalate into a full-scale war over passage through their territory [העמק דבר].
The prohibition against bothering the Ammonites is extensive. Beyond the ban on military conflict, the Israelites are not even allowed to draft the Ammonites for forced labor or other civilian services [העמק דבר, תורה תמימה, נתינה לגר]. The justification for this strict protection is that God gave the Ammonites their land as an inheritance. This gift is a direct result of the merit of Abraham, since Lot was his relative [רשב״ם, ביאור שטיינזלץ]. By pointing out how God distributed lands to different nations, He teaches the Israelites about His overall providence and instills them with confidence. Just as God cleared out ancient nations to give Lot's descendants a homeland, He will certainly secure a homeland for the Israelites, who are Abraham's direct descendants [שד״ל, רשב״ם, רלב״ג].
The protection of Ammon also originates from the personal merit of Lot's daughters. Their actions in the cave were driven by pure intentions for the sake of heaven, done solely to preserve humanity. Because of these sincere motives, the Ammonite descendants earned divine protection. Furthermore, this lineage was preserved because it would eventually produce Naamah the Ammonite, the mother of King Rehoboam of Judah, who would continue the Israelite royal dynasty [צרור המור].