A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
jos 6:1JERICHO SHUT UP. (Jos 6:1-7)
Now Jericho was straitly shut up--This verse is a parenthesis introduced to prepare the way for the directions given by the Captain of the Lord's host.
jos 6:2See, I have given into thine hand Jericho--The language intimates that a purpose already formed was about to be carried into immediate execution; and that, although the king and inhabitants of Jericho were fierce and experienced warriors, who would make a stout and determined resistance, the Lord promised a certain and easy victory over them.
jos 6:3ye shall compass the city, all ye men of war. . . . Thus shalt thou do six days, &c.--Directions are here given as to the mode of procedure. Hebrew, "horns of jubilee"; that is, the bent or crooked trumpets with which the jubilee was proclaimed. It is probable that the horns of this animal were used at first; and that afterwards, when metallic trumpets were introduced, the primitive name, as well as form of them, was traditionally continued. The design of this whole proceeding was obviously to impress the Canaanites with a sense of the divine omnipotence, to teach the Israelites a memorable lesson of faith and confidence in God's promises, and to inspire sentiments of respect and reverence for the ark as the symbol of His presence. The length of time during which those circuits were made tended the more intensely to arrest the attention, and to deepen the impressions, both of the Israelites and the enemy. The number seven was among the Israelites the symbolic seal of the covenant between God and their nation [KEIL, HENGSTENBERG].
jos 6:6Joshua . . . called the priests--The pious leader, whatever military preparations he had made, surrendered all his own views, at once and unreservedly, to the declared will of God.
jos 6:8THE CITY COMPASSED SIX DAYS. (Jos 6:8-19)
the seven priests bearing the seven trumpets . . . passed on before the Lord--before the ark, called "the ark of the covenant," for it contained the tables on which the covenant was inscribed. The procession was made in deep and solemn silence, conforming to the instructions given to the people by their leader at the outset, that they were to refrain from all acclamation and noise of any kind until he should give them a signal. It must have been a strange sight; no mound was raised, no sword drawn, no engine planted, no pioneers undermining--here were armed men, but no stroke given; they must walk and not fight. Doubtless the people of Jericho made themselves merry with the spectacle [BISHOP HALL].
jos 6:12Joshua rose early in the morning, and the priests took up the ark of the Lord--The second day's procession seems to have taken place in the morning. In all other respects, down even to the smallest details, the arrangements of the first day continued to be the rule followed on the other six.
jos 6:15on the seventh day, that they rose early about the dawning of the day, and compassed the city . . . seven times--on account of the seven circuits they had to make that day. It is evident, however, that the militia only of the Israelites had been called to the march--for it is inconceivable that two millions of people could have gone so frequently round the city in a day.
jos 6:16it came to pass at the seventh time, . . . Joshua said unto the people, Shout; for the Lord hath given you the city--This delay brought out their faith and obedience in so remarkable a manner, that it is celebrated by the apostle (Heb 11:30).
jos 6:17And the city shall be accursed--(See on Lev 27:28). The cherem, or "anathema," was a devotion to utter destruction (Deu 7:2; Deu 20:17; Sa1 15:3). When such a ban was pronounced against a hostile city, the men and animals were killed--no booty was allowed to be taken. The idols and all the precious ornaments on them were to be burned (Deu 7:25; compare Ch1 14:12). Everything was either to be destroyed or consecrated to the sanctuary. Joshua pronounced this ban on Jericho, a great and wealthy city, evidently by divine direction. The severity of the doom, accordant with the requirements of a law which was holy, just, and good, was justified, not only by the fact of its inhabitants being part of a race who had filled up their iniquities, but by their resisting the light of the recent astonishing miracle at the Jordan. Besides, as Jericho seems to have been defended by reinforcements from all the country (Jos 24:11), its destruction would paralyze all the rest of the devoted people, and thus tend to facilitate the conquest of the land; showing, as so astounding a military miracle did, that it was done, not by man, but by the power and through the anger, of God.
jos 6:18and ye, in any wise keep yourselves from the accursed thing--Generally they were at liberty to take the spoil of other cities that were captured (Deu 2:35; Deu 3:7; Jos 8:27). But this, as the first fruits of Canaan, was made an exception; nothing was to be spared but Rahab and those in her house [Jos 6:17]. A violation of these stringent orders would not only render the guilty persons obnoxious to the curse, but entail distress and adversity upon all Israel, by provoking the divine displeasure. These were the instructions given, or repeated (Deu 13:17; Deu 7:26), previous to the last act of the siege.
jos 6:20THE WALLS FALL DOWN. (Jos 6:20-21)
So the people shouted when the priests blew with the trumpets--Towards the close of the seventh circuit, the signal was given by Joshua, and on the Israelites' raising their loud war cry, the walls fell down, doubtless burying multitudes of the inhabitants in the ruins, while the besiegers, rushing in, consigned everything animate and inanimate to indiscriminate destruction (Deu 20:16-17). Jewish writers mention it as an immemorial tradition that the city fell on the Sabbath. It should be remembered that the Canaanites were incorrigible idolaters, addicted to the most horrible vices, and that the righteous judgment of God might sweep them away by the sword, as well as by famine or pestilence. There was mercy mingled with judgment in employing the sword as the instrument of punishing the guilty Canaanites, for while it was directed against one place, time was afforded for others to repent.
jos 6:22RAHAB IS SAVED. (Jos 6:22-25)
Joshua had said . . . Go into the harlot's house, and bring out thence the woman, and all that she hath--It is evident that the town walls were not demolished universally, at least all at once, for Rahab's house was allowed to stand until her relatives were rescued according to promise.
jos 6:23they brought out all her kindred, and left them without the camp of Israel--a temporary exclusion, in order that they might be cleansed from the defilement of their native idolatries and gradually trained for admission into the society of God's people.
jos 6:24burned the city . . . and all . . . therein--except the silver, gold, and other metals, which, as they would not burn, were added to the treasury of the sanctuary.
dwelleth in Israel unto this day--a proof that this book was written not long after the events related.
jos 6:26THE REBUILDER OF JERICHO CURSED. (Jos 6:26-27)
Joshua adjured them at that time--that is, imposed upon his countrymen a solemn oath, binding on themselves as well as their posterity, that they would never rebuild that city. Its destruction was designed by God to be a permanent memorial of His abhorrence of idolatry and its attendant vices.
Cursed be the man . . . that riseth up and buildeth this city Jericho--that is, makes the daring attempt to build.
he shall lay the foundation thereof in his first-born, and in his youngest son shall he set up the gates of it--shall become childless--the first beginning being marked by the death of his oldest son, and his only surviving child dying at the time of its completion. This curse was accomplished five hundred fifty years after its denunciation (see on Kg1 16:34).