Nehemiah 4:19
And I said unto the nobles, and to the rulers, and to the rest of the people, The work is great and large, and we are separated upon the wall, one far from another. And I said unto the nobles, and to the rulers, and to the rest of the people, The work is great and large, and we are separated upon the wall, one far from another.
The work on the wall was great and large, a vast undertaking extending over a long circuit. The laborers were distributed along its length, stationed far apart from one another with wide intervals between them. Because they were thus scattered and separated, they could not see or aid each other directly, so a warning sound was appointed to call them together for united action when danger appeared. At that signal they were to hasten without delay to the place under threat and gather there to meet the attack as one body. Priests with trumpets gave the alarm, and the sounding was the pledge that God Himself would fight on behalf of the builders.