“And the king said, ‘And where is your master’s son?’ Ziba said to the king, ‘Behold, he remains in Jerusalem, for he said, “Today the house of Israel will give me back the kingdom of my father.”’” (CSB – Read the chapter)
Mephibosheth was delusional. It perhaps wasn’t obvious to anyone who saw him or interacted with him on a daily basis, but there was a delusion in his heart all the same. As long as it stayed there things were pretty good for him, but now that it had shown itself, the walls of reality were going to come crashing in on him. Hard.