Some interesting thoughts on this passage below.
Joshua 3
1And Joshua rose early in the morning; and they removed from Shittim, and came to Jordan, he and all the children of Israel, and lodged there before they passed over.
2And it came to pass after three days, that the officers went through the host;
3And they commanded the people, saying, When ye see the ark of the covenant of the LORD your God, and the priests the Levites bearing it, then ye shall remove from your place, and go after it.
4Yet there shall be a space between you and it, about two thousand cubits by measure: come not near unto it, that ye may know the way by which ye must go: for ye have not passed this way heretofore.
5And Joshua said unto the people, Sanctify yourselves: for to morrow the LORD will do wonders among you.
6And Joshua spake unto the priests, saying, Take up the ark of the covenant, and pass over before the people. And they took up the ark of the covenant, and went before the people.
7And the LORD said unto Joshua, This day will I begin to magnify thee in the sight of all Israel, that they may know that, as I was with Moses, so I will be with thee.
8And thou shalt command the priests that bear the ark of the covenant, saying, When ye are come to the brink of the water of Jordan, ye shall stand still in Jordan.
9And Joshua said unto the children of Israel, Come hither, and hear the words of the LORD your God.
10And Joshua said, Hereby ye shall know that the living God is among you, and that he will without fail drive out from before you the Canaanites, and the Hittites, and the Hivites, and the Perizzites, and the Girgashites, and the Amorites, and the Jebusites.
11Behold, the ark of the covenant of the Lord of all the earth passeth over before you into Jordan.
12Now therefore take you twelve men out of the tribes of Israel, out of every tribe a man.
13And it shall come to pass, as soon as the soles of the feet of the priests that bear the ark of the LORD, the Lord of all the earth, shall rest in the waters of Jordan, that the waters of Jordan shall be cut off from the waters that come down from above; and they shall stand upon an heap.
Unlike when God delivered the Israelites from Egypt and caused a wind to blow and separate the waters, it seems that here, in entering the Promised Land, God LAID DOWN (He said He rested, resting is reclining, reclining is laying down) in the water and separated them. It sounds also like the Israelites then walked through God through the dry river bed.
Scripture indeed tells us,
"Walk in the Spirit and ye shall not fulfill the lusts of the flesh"
"It is in Him we live and move and have our being"
and
Hebrews 3
11So I sware in my wrath, They shall not enter into my rest.)
18And to whom sware he that they should not enter into his rest, but to them that believed not? 19So we see that they could not enter in because of unbelief.and Hebrews 4
3For we which have believed do enter into rest, as he said, As I have sworn in my wrath, if they shall enter into my rest: although the works were finished from the foundation of the world. 4For he spake in a certain place of the seventh day on this wise, And God did rest the seventh day from all his works.5And in this place again, If they shall enter into my rest. 6Seeing therefore it remaineth that some must enter therein, and they to whom it was first preached entered not in because of unbelief:
11Let us labour therefore to enter into that rest, lest any man fall after the same example of unbelief.
It is also interesting that in Joshua 4:19 we are told
And the people came up out of Jordan on the tenth day of the first month, and encamped in Gilgal, in the east border of Jericho.
The first month (of the sacred year) is Abib, and the 10th day is the day that the Passover lamb was to be separated from the flock.
Joshua 5:10 tell us
And the children of Israel encamped in Gilgal, and kept the passover on the fourteenth day of the month at even in the plains of Jericho.
They passed over Jordan, walking through God who laid down and parted the waters, (having first sanctified themselves), and then they kept the feast of passover and unleavened bread.
It is also interesting, the symbol of rest.
The 1st month of the sacred year (Abib) is the 7th month of the civil year (also called Nisan by is post-captivity Babylonian name)
they kept the passover on the 14th day, which is 2x7; the number seven representing rest/the sabbath/being complete. They crossed Jordan on the 10th day, the number 10 representing Divine Perfect Order.
The final verses of Joshua 3—
14And it came to pass, when the people removed from their tents, to pass over Jordan, and the priests bearing the ark of the covenant before the people;
15And as they that bare the ark were come unto Jordan, and the feet of the priests that bare the ark were dipped in the brim of the water, (for Jordan overfloweth all his banks all the time of harvest,)
16That the waters which came down from above stood and rose up upon an heap very far from the city Adam, that is beside Zaretan: and those that came down toward the sea of the plain, even the salt sea, failed, and were cut off: and the people passed over right against Jericho.
17And the priests that bare the ark of the covenant of the LORD stood firm on dry ground in the midst of Jordan, and all the Israelites passed over on dry ground, until all the people were passed clean over Jordan.
The waters backed up or piled up in heaps, we were told in v.13. God did not freeze the entire flow of the Jordan, He backed the river up and flooded out all the Canaanite cities all the way to a city called Adam... how fitting that the pure from Adam would enter in and the corrupt would be washed out.
Even as God destroyed the wicked with the Flood 897 years earlier, so also God began the cleansing of the Promised land with a flood.
What an grand entrance to the Land of Promise. That flooding out of the northern towns along the Jordan, and then the miraculous destruction of Jericho, certainly got the attention of the Canaanites—who were already in fear, the Israelites having destroyed the powerful Amorite King Sihon and Og King of Bashan, destroying those Canaanites and claiming those lands transjordan for Reuben, Gad, and half of the tribe of Manasseh.
May God deliver His people once again, once they truly have faith in Him, and sanctify themselves, and walk in Him and enter His Rest.