The Entrance is marked "FAITH"

At that time God said to Joshua, "Make stone knives and circumcise the People of Israel a second time." So Joshua made stone knives and circumcised the People of Israel at Foreskins Hill. Josh 5:2-3  The old generation who refused to enter the promised land had died off, and now this young generation was ready to enter into all God had for them. It's interesting that they first entered the promised land, then they made the sign of the covenant ~ circumcision.  Much like Abraham who believed first, and then was circumcised. If crossing the Jordan river is a picture of our entrance into the Kingdom of God, or potentially our entrance into heaven, it was critical that they did not get circumcised to enter the land, something that the Jews would discover later through Paul - you don't get enter the Kingdom by works - you are saved by faith alone! Enter by faith and obedience ~ Simply Following Jesus.