Albert Barnes Commentary Nehemiah 6:1

"Now it came to pass, when it was reported to Sanballat and Tobiah, and to Geshem the Arabian, and unto the rest of our enemies, that I had builded the wall, and that there was no breach left therein; (though even unto that time I had not set up the doors in the gates;)" — Nehemiah 6:1 (ASV)

Upon the gates - Rather, “in the gates.” This work would naturally be delayed until the last phase.