Who was hired to urge Nehemiah to hide inside the temple?

Answer: Shemaiah son of Delaiah

Tobiah and Sanballat hired Shemaiah son of Delaiah to scare Nehemiah into hiding in the temple and so discredit him.

“Later, I went to the house of Shemaiah son of Delaiah, the son of Mehetabel, who was confined to his house. He said: “Let us meet at the house of God inside the temple. Let us shut the temple doors because they are coming to kill you—by night they are coming to kill you!””— Nehemiah 6:10 (BSB)