16And the officials did not know where I had gone or what I was doing, and I had not yet told the Jews, the priests, the nobles, the officials, and the rest who were to do the work.
The reason would be that Nehemiah did not know whom he could trust. He considered it advisable that he finalize his plans before he released them. That way he could better answer whatever question and/or criticism came his way.
16 And the officials did not know where I had gone or what I was doing, and I had not yet told the Jews, the priests, the nobles, the officials, and the rest who were to do the work.