But the wall was finished the five and twentieth day of the month of Elul, in two and fifty days.

And the wall is completed in the twenty and fifth of Elul, on the fifty and second day;

So the wall was complete on the twenty-fifth day of the month Elul, in fifty-two days.

Now the wall was completed on the twenty-fifth day of the month of Elul, in fifty-two days.

Elul - The sixth month, corresponding to the latter part of August and the beginning of September.
In fifty and two days - Josephus states that the repairs of the wall occupied two years and four months. But Nehemiah's narrative is thoroughly consistent with itself, and contains in it nothing that is improbable. The walls everywhere existed at the time that he commenced his task, and only needed repairs. The work was partitioned among at least 37 working parties, who labored simultaneously, with material ready at hand; and, notwithstanding all menaces, uninterruptedly.

The twenty and fifth - of - Elul - This Jewish month answers to a part of our August and September.
Fifty and two days - I see no difficulty in supposing that several thousand workmen, each of whom was working as for God, should be able to complete this wall in fifty-two days. There is little doubt that several parts of the old wall were entire; in many places the foundations still remained; there were all the materials of the old wall still at hand; and though they had to clear and carry away much rubbish, yet they do not appear to have had any stones to quarry. The work mentioned here was little when compared to what Caesar did in Gaul and other places; and to what Titus did at Jerusalem, who built a wall round Jerusalem of five thousand paces in three days, besides, thirteen towers of ten stadia in circuit. And Quintus Curtius and Arrian inform us that Alexander the Great built the walls of Alexandria, on the Tanais, which were nearly eight miles in compass, in the space of between twenty and thirty days. Nehemiah therefore had time sufficient in fifty-two days to repair and restore the walls of Jerusalem. See Calmet on this place.

So the wall was finished in the twenty and fifth [day] of [the month] (h) Elul, in (i) fifty and two days.
(h) Which was the sixth month and contained part of August, and part of September.
(i) After I had sent Sanballat his answer.

So the wall was finished in the twenty fifth day of the month Elul,.... The sixth month, answering to part of August and part of September:
in fifty and two days; which Aben Ezra reckons from the time that Sanballat sent his letter to Nehemiah, when no more were wanting than to set the doors upon the gates, Nehemiah 6:1, but rather these, with Jarchi, must be reckoned from the time the building was begun; which, reckoning back from the twenty fifth of Elul, it will appear it was begun the third day of the fifth month Ab; nor need this be thought incredible, considering the number of workmen, their ardour and diligence in building, and that the walls were not wholly built all around, only repaired, and breaches made up, and much of the old materials were made use of, which were at hand, and stone unhewed, and especially being attended with the blessing of God, which succeeded the undertaking: nor are there wanting examples similar to this; and as it is observed by many from Curtius (x), the walls of new Alexandria, which were sixty furlongs in length, or more than seven miles, were finished in seventeen days; if Nicephorus (y) is to be credited, the high walls which surrounded Constantinople, and were twenty miles in circumference, were finished in two months time. Josephus is not to be regarded, who, contrary to the Scriptures says (z), this wall of Jerusalem was two years and four months in building.
(x) Hist. l. 7. c. 6. Justin e Trogo, l. 12. c. 5. (y) Hist. l. 14. c. 1. (z) Antiqu. l. 11. c. 5. sect. 8.

The wall was begun and finished in fifty-two days, though they rested on the sabbaths. A great deal of work may be done in a little time, if we set about it in earnest, and keep close to it. See the mischief of marrying with strangers. When men once became akin to Tobiah, they soon became sworn to him. A sinful love leads to a sinful league. The enemy of souls employs many instruments, and forms many projects, to bring reproach on the active servants of God, or to take them from their work. But we should follow the example of Him who laid down his life for the sheep. Those that simply cleave to the Lord and his work will be supported.

The wall completed, and the impression made by this work upon the enemies of the Jews. - Nehemiah 6:15 The wall was finished on the twenty-fifth day of the month Elul, i.e., of the sixth month, in fifty-two days. According to this statement, it must have been begun on the third day of the fifth month (Ab). The year is not mentioned, the before-named (Nehemiah 2:1) twentieth year of Artaxerxes being intended. This agrees with the other chronological statements of this book. For, according to Nehemiah 2:1, it was in Nisan (the first month) of this year that Nehemiah entreated permission of the king to go to Jerusalem; and we learn from Nehemiah 5:14 and Nehemiah 13:6 that he was governor in Jerusalem from the twentieth year onwards, and must therefore have set out for that place immediately after receiving the royal permission. In this case, he might well arrive in Jerusalem before the expiration of the fourth month. He then surveyed the wall, and called a public assembly for the purpose of urging the whole community to enter heartily upon the work of restoration (Nehemiah 2:11-17). All this might take place in the course of the fourth month, so that the work could be actually taken in hand in the fifth. Nor is there any reasonable ground, as Bertheau has already shown, for doubting the correctness of the statement, that the building was completed in fifty-two days, and (with Ewald) altering the fifty-two days into two years and four months.
(Note: Ewald, Gesch. iv. p. 178, thinks that traces of the correct reading of this verse are found in the statement of Josephus, Ant. xi. 5. 7f., that the wall of Jerusalem was finished in two years and four months, and that the word וּשׁנתים may have been omitted from Nehemiah 6:15 by an ancient clerical error, though he is obliged to admit that Josephus in other instances gives no trustworthy dates concerning Nehemiah, whom he makes arrive at Jerusalem in the twenty-fifth, and complete the wall in the twenty-eight year of Xerxes. On the other hand, Bertheau has already remarked, that even if שׁנתים is supplied, no agreement with the statement of Josephus is obtained, since the question still remains how four months can be made out of fifty-two days, or vice versa, fifty-two days of four months. In fact, it is vain to seek for any common ground on which these two different statements can be harmonized; and hence the two years and four months of Josephus can scarcely be regarded as furnishing traces of another reading of the text.)
For we must in this case consider, 1st, the necessity for hastening the work repeatedly pointed out by Nehemiah; 2nd, the zeal and relatively very large number of builders - the whole community, both the inhabitants of Jerusalem and the men of Jericho, Tekoa, Gibeon, Mizpah, etc. having combined their efforts; 3rd, that the kind of exertion demanded by such laborious work and unintermitted watchfulness as are described Nehemiah 4, though it might be continued for fifty-two days, could scarcely endure during a longer period; and lastly, the amount of the work itself, which must not be regarded as the rebuilding of the whole wall, but only as the restoration of those portions that had been destroyed, the repair of the breaches (Nehemiah 1:3; Nehemiah 2:13; Nehemiah 6:1), and of the ruined gates, - a large portion of wall and at least one gate having remained uninjured.). To this must be added that the material, so far as stone was concerned, was close at hand, stone needing for the most part to be merely brought out of the ruins; besides which, materials of all kind might have been collected and prepared beforehand. It is, moreover, incorrect to compute the extent of this fortified wall by the extent of the wall of modern Jerusalem.

Elul - Answering part to our August, and part to September.