The division of the territory east of the Jordan River represents more than a simple drawing of geographical borders. It is a deeply historical and spiritual process that fulfills ancient promises. Entrusting this vast and challenging region to half the tribe of Manasseh involved both strategic and spiritual considerations. Historically, this territory was inhabited by giants and mighty warriors, requiring immense physical strength to secure and maintain [מלבי״ם]. Beyond military strategy, Moses sought to forge an unbreakable national and spiritual bond between the tribes settling east of the Jordan and those crossing into the land of Israel. By placing half of Manasseh—a tribe renowned for its deep love of the land and its abundance of scholars—in this eastern territory, he ensured a strong, enduring connection between the two halves of the nation across the river [ברכת אשר על התורה].
The description of the entire district as a single, unified region serves to highlight the sheer magnitude of the miracles God performed during its conquest. This area was densely populated and filled with heavily fortified cities. Had the Israelites been forced to lay siege to each city individually, the military campaign would have dragged on for years. Presenting the entire district as one conquered whole underscores the rapid, miraculous collapse of Og and his kingdom [שפתי כהן].
The territory came to be known as the land of Rephaim, either named directly after Og, the king of Bashan who ruled it, or because it originally belonged to the Rephaim nation and was held by Og, the very last survivor of those ancient giants [רמב״ן, הטור הארוך, ביאור יש״ר]. A specific emphasis is placed on identifying this exact region to highlight that this is the precise land of Rephaim God promised to Abraham during the Covenant between the Parts [רש״י, רשב״ם, רבנו בחיי]. This careful distinction separates it from other territories, such as Ammon, which were also historically inhabited by giants and known by the same name, but were never included in God's divine promise to Abraham [מזרחי, שפתי חכמים, ברכת אשר על התורה].
Identifying this eastern territory as part of the promise to Abraham clarifies its unique spiritual status. Even though it is included among the lands promised to Abraham, its level of holiness is considered lower than that of the land of Israel west of the Jordan. Initially, God intended for this eastern region to be conquered merely so the Israelites could benefit from its spoils, rather than serving as a primary homeland. Nevertheless, because the land was conquered before God and officially distributed to the tribes, it was infused with sanctity, and the specific laws pertaining to the holy land fully apply to it [אור החיים].