John Gill Commentary Nehemiah 2:19

"But when Sanballat the Horonite, and Tobiah the servant, the Ammonite, and Geshem the Arabian, heard it, they laughed us to scorn, and despised us, and said, What is this thing that ye do? will ye rebel against the king?" — Nehemiah 2:19 (ASV)

But when Sanballat the Horonite, and Tobiah the servant, the
Ammonite, and Geshem the Arabian
This third man might be both an Arabian by birth, and governor of some part of Arabia near Judea:

heard it ;
of their beginning to build:

they laughed us to scorn, and despised us ;
as very silly people, that undertook what they could never perform:

and said ;
adding threatenings to their scoffs:

what is this thing that you do ?
do you know what you are about? have you any authority to do it? it is unlawful, you will certainly suffer for it:

will you rebel against the king ?
the king of Persia; it will be deemed rebellion and treason, and you will be taken up and treated as rebels and traitors; take care what you do, be it at your peril if you proceed.