Charles Ellicott Commentary 2 Samuel 4:1

"And when [Ish-bosheth], Saul`s son, heard that Abner was dead in Hebron, his hands became feeble, and all the Israelites were troubled." — 2 Samuel 4:1 (ASV)

All the Israelites were troubled. —The death of Abner affected both Ish-bosheth and his people. For the former, his hands were feeble, the whole support and strength of his throne being gone; the latter were troubled because they had been carrying on negotiations with David through Abner, and these were now thrown into confusion, and it became uncertain how they might result.