Tafsiran Bilangan 3:2: Kitzur Ba'al HaTurim, Sforno & Rav Hirsch

These are the names of the sons of Aharon, the firstborn, Nadav, and Avihu, Elazar and Isamar. There is a pause between the words “the firstborn” and “Nadav” because it does not refer to Nadav who died without children, and there is no practical ramification of his being the firstborn. Rather, it refers to Aharon who was the firstborn ahead of Moshe.

ואלה שמות בני אהרן; each one of them was mentioned by his name, i.e. not only because he was a son of an illustrious father such as Aaron.

V. 2. Eigentümlich ist die Akzentuierung. Es ist, als ob der Bericht mit schmerzlicher Pause zuerst auf Nadab und dann auf Abihu ruht und dann rasch Elasar und Itamar beifügt.