דברי הימים א, פרק כ״ד, פסוק ב׳

The passing of Aaron's older sons created a significant shift in the lineage of the priesthood. The tragedy occurred during their father's lifetime, forcing a change in the expected order of succession [מצודת דוד, ביאור שטיינזלץ].

The absence of male heirs for Nadab and Abihu carries a dual significance. On one hand, it leaves open the possibility that they had daughters who may have married their cousins, though biblical records sometimes note individuals dying without any offspring at all [ביאור שטיינזלץ].

More importantly, this lack of male heirs dictated the future of the priestly line. The right to the priesthood transferred to their younger brothers, Eleazar and Ithamar, entirely because there were no sons to inherit the role. Had Nadab and Abihu fathered sons, those children would have automatically held priority over their uncles for the High Priesthood. This rule of succession, where a son takes precedence over a brother, is clearly seen later during the era of the Return to Zion. At that time, Joshua the son of Jehozadak assumed the role of High Priest by virtue of being the firstborn's son, taking precedence over his uncle Ezra [רש״י].

As a direct result of these events, the responsibility fell to Eleazar and Ithamar. They stepped forward to serve as priests before God, ensuring the continuation of the sacred lineage in place of their older brothers [מצודת דוד, ביאור שטיינזלץ].