Nehemiah 4:18-21 NIV
and each of the builders wore his sword at his side as he worked. But the man who sounded the trumpet stayed with me.
Then I said to the nobles, the officials and the rest of the people, “The work is extensive and spread out, and we are widely separated from each other along the wall. Wherever you hear the sound of the trumpet, join us there. Our God will fight for us!”
So we continued the work with half the men holding spears, from the first light of dawn till the stars came out.
NIV: New International Version