John Gill Commentary 2 Samuel 13:35

"And Jonadab said unto the king, Behold, the king`s sons are come: as thy servant said, so it is." — 2 Samuel 13:35 (ASV)

And Jonadab said to the king, behold, the king's sons come ,
&c.] For as they came nearer, it was plainly discovered that they were the king's sons, seen on the side of the hill:

as your servant said, so it is ;
he seems to applaud himself, and exult at his penetration and foresight.