This passage from the insprired book of Jashur, quoted from in the Holy Bible as Authoritative.
This passage shows the march began on the first day of the moon, and continued through until the 7th day of the moon, in English called "month".

It also illustrates that they kept the Lunar Weekly cycle, as they did not march upon the 8th day of the moon, which is the 7th day Shabat of the weekly cycle, as Scripture plainly states that the New Moon Day can never be one of the days of the weekly cycle, proven in Ezekiel 46:1, and 3, and mathematically proven in Exodus chapter 16.

This disproves the lie of the unbreakable cycle of 7's from creation week until now, false theory, which cannot be substantiated from even one verse in Scripture.

Schaff-Herzog

     From The Universal Jewish Encyclopedia, Vol. 5, p. 410:
 

 

Book of Jashur Chapter 88

14 And it was in the second month, on the first day of the month, that YeHovah said to YeHoshua, Rise up, behold I have given Jericho into thy hand with all the people thereof; and all your fighting men shall go round the city, once each day, thus shall you do for six days.
15 And the priests shall blow upon trumpets, and when you shall hear the sound of the trumpet, all the people shall give a great shouting, that the walls of the city shall fall down; all the people shall go up every man against his opponent.
16 And YeHoshua did so according to all that YeHovah had commanded him.
17 And on the seventh day they went round the city seven times, and the priests blew upon trumpets.
18 And at the seventh round, YeHoshua said to the people, Shout, for YeHovah has delivered the whole city into our hands.
19 Only the city and all that it contains shall be accursed to YeHovah, and keep yourselves from the accursed thing, lest you make the camp of Israel accursed and trouble it.
20 But all the silver and gold and brass and iron shall be consecrated to YeHovah, they shall come into the treasury of YeHovah.
21 And the people blew upon trumpets and made a great shouting, and the walls of Jericho fell down, and all the people went up, every man straight before him, and they took the city and utterly destroyed all that was in it, both man and woman, young and old, ox and sheep and ass, with the edge of the sword.
22 And they burned the whole city with fire; only the vessels of silver and gold, and brass and iron, they put into the treasury of YeHovah.
23 And YeHoshua swore at that time, saying, Cursed be the man who builds Jericho; he shall lay the foundation thereof in his first-born, and in his youngest son shall he set up the gates thereof.