Chapter 3: Crossing the Jordan

1. The day before the crossing-The nation is instructed that they will travel and cross the Jordan:

The Jewish people encamp by the Jordan river: Yehoshua woke up early in the morning, and the entire camp traveled from Shitim and arrived at the banks of the Jordan river. They slept there prior to crossing it.
The police instruct the nation: At the end of the three days [from when the spies returned[1]] the police scattered amongst the camp and instructed the nation that when they see the ark of G-d being carried by the Kohanim and Levites they are to travel from their place and follow it. They were instructed to keep a distance of 2000 Amos from the Aron of Hashem [but not more] in order so they see the path of travel, as they are unfamiliar with the roads.
Yehoshua instructs the nation: Yehoshua instructed the nation to prepare [and sanctify[2]] themselves, as the next day Hashem will perform miracles on their behalf. [The next day[3]] Yehoshua instructed the Kohanim to carry the Aron Habris and lead the nation in travel, and so the Kohanim carried the Aron at the head of the nation.

Hashem instructs Yehoshua: Hashem said to Yehoshua as follows: “Today I will make your prestige grow amongst the Jewish people, as they will see that just as I was with Moshe so too, I will be with you. Now, command the Kohanim who are carrying the Aron Habris that upon arriving at the shore of the Jorden river they are to stop traveling [and allow the entire Jewish people to cross, and only afterwards may they continue their travel[4]].”
Yehoshua relates the commands of G-d to the nation and instruct them in crossing the Jordan: Yehoshua summoned the Jewish people to come to him so he can instruct them what G-d had told him. He told them as follows: This is the sign that a living G-d is amongst you and that He will destroy for you the seven Canaanite nations, the Canaani, Hiti, Chivi, Perizi, Girgashi, Emori, and Yevusi. The Aron Habris of G-d will pass before you into the Jordan [and cause the waters to split[5]]. Now, take from amongst you twelve representatives, one person per tribe [so they be already designated and available for instructions after we cross the Jordan]. When the Kohanim, who are carrying the Aron of Hashem, will rest the palm of their feet into the waters of the Jordan, the waters that are coming from above will split and accumulate until they form a single mound.

The water splits: The nation traveled from their tents to cross the Jordan and the Kohanim who carried the Aron Habris led the journey. When the Kohanim arrived at the Jordan they immersed their feet into the waters of the Jordan, which was full to capacity during that period [of Nissan, after the rain season]. The waters that were coming from above came to a standstill and accumulated to a single mound. The river became dried from the location of the city Adam until the Dead Sea, which is where all the descending waters entered.
The nation passes: The nation then passed through the now dried river, opposite the city of Jericho. The Kohanim remained standing in their position [by the shore of the river] holding the Aron Habris until all the Jewish people passed through the dried riverbed.

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[1] See Radak 3:2; However, see Metzudos David who implies that this took place three days before the travel

[2] Metzudas David 3:5

[3] Rashi 3:6

[4] Rashi 3:8

[5] Radak 3:10