בראשית, פרק י״א, פסוק י״ג

The lifespans of the early generations often follow a consistent numerical pattern. After the birth of his son Shelah, Arpachshad lived for another four hundred and three years. This timeframe is built upon a base number of four hundred years, a foundational figure that defines the lifespans of all three generations immediately following Shem.

The additional three years fit directly into this pattern, as they equal exactly thirty-six months. Ultimately, Arpachshad lived a total of four hundred and thirty-eight years. This complete lifespan reflects the same calculated framework, consisting of the initial base number of four hundred years combined with an additional four hundred and fifty-six months [קאסוטו].