Right before entering the land, the covenant between God and the Israelites is renewed through a public ceremony. The tribes divide into two groups, standing on two separate mountains to formally accept a series of blessings and curses [שד״ל]. The execution of this dramatic event was highly structured. Rather than reciting all the blessings followed by all the curses, the ceremony alternated. A single blessing was read aloud, immediately followed by its corresponding curse [תורה תמימה].
There is a careful distinction in how the two groups are directed. While the tribes on the first mountain are told to bless the people, the tribes on the second mountain are simply told to stand for the curse, rather than to actively curse the people. The primary approach among commentators is that the Torah intentionally uses gentle language to avoid expressing something negative or placing a direct curse on the Israelites, who are inherently a blessed nation. Standing for the curse means they were simply standing in relation to it [ביאור שטיינזלץ], though another perspective suggests this phrasing implies the tribes actually maintained control over the curse [נחל קדומים]. Furthermore, the curses recited during this gathering were specifically aimed at sins committed in secret. Offenses done in public are naturally handled and punished by the standard court system. For this reason, there is no curse mentioned for a sin like sleeping with a married woman, because such a public offense would ultimately be discovered and judged normally [ריב״א].
The arrangement of the tribes on the mountain of the curse reveals a deliberate pattern. While the mountain of blessing was occupied by the sons of the primary wives, the mountain of the curse was assigned to the four sons of the handmaids: Gad, Asher, Dan, and Naphtali. They were joined by two of Leah's sons: Zebulun, who was her youngest, and Reuben [ריב״א]. Placing Reuben on this specific mountain carries a profound message of personal atonement. Because of his past sin involving his father's bed, he was positioned there to personally answer "Amen" to the specific curse against one who lies with his father's wife, thereby accepting the judgment upon himself [ריב״א, נחל קדומים]. Asher's presence on this mountain also carries hidden significance, serving as a subtle reminder of the unique importance of his daughters, who would later marry high priests and kings [נחל קדומים].
Looking forward into history, a tragic parallel emerges from this arrangement. Every single tribe that stood on the mountain to hear the curses was ultimately among those lost during the later exile of the ten tribes [קונטרס חיבה יתירה].