The man whom thou seekest is as if all returned, i. e. the death of that man whom thou seekest to destroy is no less considerable to thee, than if all the people that follow him should desert him and return unto thee.
Related Commentaries of 2 Samuel 17:3
2 Samuel 17:3
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.