5.  young  men--priests  
  (Ex  19:22),
  probably  the  oldest  sons  of  particular  families,  who  acted  under  the
  direction  of  Moses.
  
         
  oxen--Other  animals,  though  not  mentioned,  were  offered  in  
  sacrifice
  (Heb  9:18-20).
JFB.
Picture Study Bible