Numbers 26:60 Kabbalah

וַיִּוָּלֵ֣ד לְאַהֲרֹ֔ן אֶת־נָדָ֖ב וְאֶת־אֲבִיה֑וּא אֶת־אֶלְעָזָ֖ר וְאֶת־אִיתָמָֽר׃

And unto Aaron were born Nadab and Abihu, Eleazar and Ithamar.

Read kabbalistic (mystical) interpretation of Numbers 26:60: and classical mystical sources.