Such is the start of the counsel given by Vidura to the blind king Dhritarashtra.
Why had sleeplessness overtaken him?
Because Sanjay had taken the king's permission to go sleep!
Because Sanjay had returned from an unsuccessful journey to Upalavya where he had been sent by the king with instructions to not say anything that would incite the Pandavas to war.
Because, while Sanjay had told Dhritarashtra what he thought, he had still not delivered Ajatshatru's message for the king, which he would do only in the morning.
The morning that was yet to come filled Dhritarashtra with dread.
And thus sleeplessness.