Nehemiah is, here, finishing the wall of Jerusalem, and yet still has trouble created [for] him by his enemies.
Tobiah and the other adversaries of the Jews had the mortification to see the wall built up, notwithstanding all their attempts to hinder it. The wall was begun and finished in fifty-two days, and yet we have reason to believe they rested on the sabbaths (verse 15). Many were employed, and there was room for them. What they did, they did cheerfully, and minded their business because they loved it. The threats of their enemies, which were intended to weaken them, it is likely, quickened them to go on with their work the more vigorously, that they might get it done before the enemy came. Thus, “out of the eater came forth meat.” See what a great deal of work may be done in a little time if we would set about it in earnest and keep close to it. When the enemies heard that the wall was finished before they thought it was well begun, and when they doubted not but to put a stop to it, they were “much cast down in their own eyes” (verse 16). They were ashamed of their own confidence that they should cause the work to cease, [and] they were crestfallen upon the disappointment. They envied the prosperity and success of the Jews [and] grieved to see the walls of Jerusalem built while, it may be, the kings of Persia had not permitted them thus to fortify the cities of Samaria. When Cain envied his brother, his countenance fell (Genesis 4.5). – Matthew Henry (1662-1714), commenting on Nehemiah 6.15-19.