Moments before the historic entry into the Land of Israel, the Israelites stand at the edge of the Jordan River. This crossing is not merely a geographic transition, but a powerful divine display designed to instill confidence in the people ahead of their upcoming conquest.
Leading the way is the Ark of the Covenant, associated with a striking title: the Lord of all the earth. The primary approach among commentators is that this refers to the Ark belonging to God, who is the Master of the entire world [רש״י, מצודת דוד, רד״ק, ביאור שטיינזלץ]. Alternatively, the Ark itself is metaphorically given this divine title because God's glory rests upon it, a concept seen elsewhere where the Ark bears God's own name [רד״ק].
The choice to highlight God as the Master of the entire earth at this specific moment is highly intentional. It demonstrates that God has absolute control over nature and can alter it according to His will. This reality is about to be proven when the rushing waters of the Jordan, which naturally flow downward with tremendous force, suddenly stand upright like a solid wall [רד״ק, אברבנאל]. The message to the people is profound: they are not just following a physical object. God Himself is crossing ahead of them. He is not confined to a single location or limited to the physical Ark, because the entire earth is subject to Him, and He operates far beyond the bounds of humans or angels [אלשיך].
The Ark leading the camp carries both military and spiritual weight. Much like a commander marching at the head of his troops, God crosses the river first to fight on behalf of Israel. The miracle of the splitting waters serves as a direct proof to the people. It guarantees that just as the mighty river retreats before God's presence, the Canaanite nations waiting on the other side will also be struck with fear and flee before them [אברבנאל].
Because the Israelite camp was so massive, the vast majority of the people would not be able to see the exact moment the waters stopped as the priests carrying the Ark stepped into the river. To solve this, twelve representatives, one from each tribe, are selected to walk closely beside the Ark, following standard military formations. Their role is to witness the miracle up close so they can testify about it to the rest of the nation. Additionally, they are tasked with crossing over to locate and prepare the specific camping grounds for each tribe on the other side of the river [אלשיך, אברבנאל].