Bible Notes Online - Joshua 3 - ESV
Commentary

v1: Having received the information from the spies, Joshua started to prepare the people.

v2: Delegated leadership, as the officers took instructions through the camp.

v3: The people had to follow the ark of the covenant, which gave God's direction.

v4: They had to keep a distance from the ark, as a mark of reverence. But they had never been this way before; there was the necessity of trust, in God, and in their leaders, and especially in Joshua.

v5: The people's part was to be sanctified, ready to receive God's blessing.

v6: The role of the priests, in leading the way. The people had to follow.

v7: God would magnify Joshua in the sight of the people; this was fulfilled in 4.14. As with Moses, the people learned to respect their leader.

Joshua had never shared the people's grumbling and rebellion, he had always been loyal to Moses, and now he expects that the people will be loyal to him.

v9-13: "Certainly", or "without fail"; victory was certain, for God had promised it. The people would enter the land, and they would occupy it. As part of the great miracle of the occupation of the land, there was the (lesser) miracle of the waters of the Jordan ceasing to let the people cross.

v14-15: The Jordan was in flood; in contrast, in 2.7, the spies crossed by a ford. Presumably a more convenient spot had to be found for many thousands of people. We see God's power, that a flooding river presents no barrier.

The arrival at harvest time was also part of God's provision, as the miraculous supply of manna ceased. It is interesting that the river flooded at harvest time, which was the time of Passover (5.10); we think this is unusual, but the writer’s comment is evidence of detailed truth.

v16-17: As soon as the priests' feet touched the water, the waters ceased, and "piled up" a distance away, giving them space to cross over. This remained the case whilst the whole people crossed over; presumably this was a period of several hours. We note too that the priests stood on dry, not muddy, ground. This was part of the miracle that God did.