Albert Barnes Commentary 2 Samuel 17:3

"and I will bring back all the people unto thee: the man whom thou seekest is as if all returned: [so] all the people shall be in peace." — 2 Samuel 17:3 (ASV)

The man whom you seek—namely, David. Ahithophel means to say, "If I can only strike down David, there will be no civil war; all the people will peaceably submit."