John Gill Commentary 2 Samuel 20:25

"and Sheva was scribe; and Zadok and Abiathar were priests;" — 2 Samuel 20:25 (ASV)

And Sheva [was] scribe
Either the same with Benaiah, or he was dead or removed, and Sheva was put in his place, see (2 Samuel 8:17) ;

and Zadok and Abiathar [were] the priests ;
as before; (See Gill on 2 Samuel 8:17).