בְּנֵ֖י מְרָרִ֑י לְמִשְׁפְּחֹתָ֥ם לְבֵית־אֲבֹתָ֖ם תִּפְקֹ֥ד אֹתָֽם׃
As for the sons of Merari, thou shalt number them by their families, by their fathers’houses;
Read kabbalistic (mystical) interpretation of Numbers 4:29: and classical mystical sources.