וְאֵ֛לֶּה שְׁמ֥וֹת בְּֽנֵי־אַהֲרֹ֖ן הַבְּכ֣וֹר ׀ נָדָ֑ב וַאֲבִיה֕וּא אֶלְעָזָ֖ר וְאִיתָמָֽר׃
And these are the names of the sons of Aaron: Nadab the first-born, and Abihu, Eleazar, and Ithamar.
Read halakhic rulings (Jewish law) on Numbers 3:2: and classical halakhic sources.