בראשית, פרק י״א, פסוק י׳

Following the sweeping history of all humanity, the focus suddenly narrows to a single chosen family. A precise lineage serves as a historical and spiritual bridge connecting the new world that emerged after the flood to the arrival of Abraham, the tenth generation from Shem. This transition marks the dawn of the Israelite nation.

Unlike the other sons of Noah, Shem is introduced with a special, celebratory emphasis because heaven and earth were created for the sake of his descendants [חומת אנך]. This introduction also highlights a sharp contrast with the past. While previous generations were wicked and ultimately perished, Shem's descendants are righteous, ensuring that their lineage will endure [חזקוני]. Furthermore, the grim refrain noting the death of each individual, which appeared constantly in the earlier generations from Adam to Noah, is entirely absent from this lineage. This omission hints at the eternal nature of the Davidic dynasty that will eventually emerge from Shem, and suggests that the future resurrection of the dead is primarily destined for his offspring [רבנו בחיי].

The names recorded in this family tree are far more than a simple registry. They reflect a gradual process of spiritual development and active protest against the surrounding society. This spiritual uprising began within Shem's family and reached its peak with his descendant Eber, who represented complete opposition to the prevailing culture of his time [רש ר הירש].

Shem fathered Arpachshad at the age of one hundred. Although Arpachshad was actually Shem's third son, he takes center stage while his older brothers are ignored, simply because Abraham is destined to descend from him [רד״ק, משכיל לדוד]. Exact ages are provided throughout this lineage to maintain a strict chronological timeline from the creation of the world to Abraham, thereby making the reality of creation widely known [רד״ק].

The timing of this birth, occurring two years after the flood, presents a slight chronological puzzle. Noah began having children at the age of five hundred, and the flood occurred when he was six hundred. If so, Shem should have been older than one hundred two years after the flood. The accepted resolution is that Noah's sons were not born in the same year. The firstborn, Japheth, was born when Noah was five hundred, while Shem was born two years later. Therefore, Shem was ninety-eight when the flood began, reaching one hundred exactly two years later [ביאור יש״ר, קאסוטו]. The reference to the time after the flood specifically points to the moment the rains first began to fall [קאסוטו, מחוקקי יהודה].

This post-flood era is marked by a gradual and significant decline in human life expectancy. Following the destruction, the Divine abundance that sustains the world is no longer granted unconditionally. Instead, it relies on humanity's own efforts toward spiritual refinement. While this shift guarantees that God will never again destroy the world, it also reduces the intensity of the Divine life force flowing into creation, which naturally leads to shorter lifespans [חומש קה״ת]. Additionally, the specific mention of a two-year timeframe echoes prophetic warnings of physical upheaval, indicating that the flood was accompanied by a massive, catastrophic earthquake [בעל הטורים].