Numbers 2:12

And those which pitch by him [shall be] the tribe of Simeon,
&c.] Under his standard, and on one side of it; Reuben and Simeon being brothers by the mother as well as the father's side, might well be thought to agree together; and Reuben being the eldest brother, and the eldest of all Jacob's sons, Simeon would not grudge to pitch under him:

and the captain of the children of Simeon [shall be] Shelumiel the son
of Zurishaddai;
of whom see ( Numbers 1:6 ) ( 7:36 ) .