I Chronicles 4:27 Kabbalah

וּלְשִׁמְעִ֞י בָּנִ֨ים שִׁשָּׁ֤ה עָשָׂר֙ וּבָנ֣וֹת שֵׁ֔שׁ וּלְאֶחָ֕יו אֵ֖ין בָּנִ֣ים רַבִּ֑ים וְכֹל֙ מִשְׁפַּחְתָּ֔ם לֹ֥א הִרְבּ֖וּ עַד־בְּנֵ֥י יְהוּדָֽה׃ (ס)

And Shimei had sixteen sons and six daughters; but his brethren had not many children, neither did all their family multiply, like to the children of Judah.

Read kabbalistic (mystical) interpretation of I Chronicles 4:27: and classical mystical sources.