דֶּ֣גֶל מַחֲנֵ֧ה רְאוּבֵ֛ן תֵּימָ֖נָה לְצִבְאֹתָ֑ם וְנָשִׂיא֙ לִבְנֵ֣י רְאוּבֵ֔ן אֱלִיצ֖וּר בֶּן־שְׁדֵיאֽוּר׃
On the south side shall be the standard of the camp of Reuben according to their hosts; the prince of the children of Reuben being Elizur the son of Shedeur,
Read kabbalistic (mystical) interpretation of Numbers 2:10: and classical mystical sources.