The Babylonian soldiers had dismantled the wall years ago when they captured the city (2 Chronicles 36:19). Some of these stones had rolled a distance from the wall and so had to be carried back. We are also to think of the mortar needed to bind the stones into a structure. Instead, though, of carrying the burden with two hands, the stone or mortar, etc, was -shall we say- strapped to the shoulder in a bag or basket so as to leave one hand free to carry a weapon. That way, when the leaders
sounded the alarm, every worker was immediately armed for fighting. We should also realize that those who carried burdens
were scattered some distance from the wall as they retrieved stones and/or delivered mortar. So Nehemiah’s servants
(Nehemiah 4:16) could not protect them in the same way they could protect the builders
17 who were building on the wall. Those who carried burdens were loaded in such a way that each labored on the work with one hand and held his weapon with the other.