בראשית, פרק י״א, פסוק י״ב

Genealogical records often follow a predictable rhythm, but the transition between Shem and his son Arpachshad takes a slightly different approach to maintain an unbroken story. Because the previous account does not conclude with a final summary of Shem's total years, the focus pivots immediately to his son. This rapid shift serves to smoothly hand off the narrative, essentially signaling a new focus on Arpachshad and the exact time in his life when his firstborn arrived [קאסוטו].

He became a father at thirty-five years old. This specific age is understood to be based on a distinct method of calculation, representing seven units of time that each consist of sixty months. By recording the birth of his son Shelah, the narrative deliberately links this detailed family line back to the broader ancestral chain that was established earlier in the history [קאסוטו].