John Gill Commentary 2 Samuel 19:36

"Thy servant would but just go over the Jordan with the king: and why should the king recompense it me with such a reward?" — 2 Samuel 19:36 (ASV)

Your servant will go a little way over Jordan with the king ,
&c.] That is, go a little way after he was over Jordan with him, and then return to his own city:

and why should the king recompense it with such a reward ?
the sense is, why should the king recompense so trifling a thing as I have done, and which was but my duty, with such a reward, as to maintain me in so grand a manner at his court?