The covenant made at the plains of Moab transcends the physical limitations of time and space, extending far beyond the people standing there that day into an eternal dimension. This sweeping declaration eliminates any thought that the commitment to the Torah is temporary or can ever be canceled [רש״ר הירש, מלבי״ם]. A natural question arises: how can an oath legally bind future generations who have not yet been born? [כלי יקר, תולדות יצחק]. Commentators resolve this through two main avenues, one metaphysical and the other legal.
The primary approach among commentators is that every soul destined to be born until the end of time was spiritually present at this event. Even though their physical bodies did not yet exist, these souls stood before God much like angels. This spiritual gathering included the souls of young children who had not yet reached maturity [אלשיך], the souls of those who had already passed away [שפתי כהן], and all future prophets. These prophets actually received their future visions at this moment, even though they were only granted permission to speak them in their respective generations [רבנו בחיי].
On a legal and historical level, the forefathers are viewed as the root, while the descendants are the branches; therefore, the root has the power to obligate its offspring [רבנו בחיי]. Furthermore, because God redeemed the Israelites from slavery in Egypt, they essentially became His servants. Just as the children of a servant belong to the master, the descendants of the Israelites remain perpetually bound to God [תולדות יצחק]. The current generation accepted the covenant not merely for themselves, but acting as authorized representatives to bind all future generations [אור החיים], as well as any converts who would eventually join the nation [רלב״ג, בכור שור].
This raises the issue of why a new covenant involving future generations was necessary at all, given that an agreement had already been established at Mount Sinai. One explanation is that at Sinai, the Israelites were willing to commit themselves but hesitated to bind their children. Having only known the idols of Egypt, they feared there might be a stronger power in the world. However, after wandering among various nations and realizing that all foreign idols were worthless, they understood that accepting the covenant was an absolute privilege. According to Jewish law, a privilege can be accepted on behalf of someone even in their absence [תולדות יצחק].
Other scholars offer different perspectives on this necessity. Some suggest that the forefathers required this oath because they had been exposed to the idols of Egypt and surrounding nations, leaving them vulnerable to straying. The future generations, while not exposed to these idols, still needed the oath to prevent them from inheriting an innate tendency to sin from their ancestors [כלי יקר]. Another view proposes that the renewed covenant, which carefully distinguished between those who were present and those who were absent, was actually designed to ease the harshness of the punishments and lighten the heavy burden of mutual responsibility that characterized the agreement at Sinai [שפתי כהן].
To prevent any legal evasion, Moses emphasizes to the people that the oath is binding according to the understanding of God and the earthly court. It cannot be bypassed by any hidden intentions or personal interpretations that the swearers might secretly hold in their hearts [תורה תמימה]. Ultimately, despite the heavy burden of the covenant and its associated curses, the inclusion of future generations carries a profound message of comfort. Just as a master who severely disciplines his servant demonstrates that he has no intention of selling him or letting him go, God's strict warnings and the eternal nature of this agreement prove that He desires His people forever and will never abandon them [העמק דבר].