New Defender's Study Bible Notes
3:4 two thousand cubits. This was a distance of more than half a mile, enabling everyone in the camp to see the ark, and also stressing its sacred character; it was normally kept inside the holy place, where none could see it at all.
3:16 upon an heap. A quasi-naturalistic explanation of this miracle suggests a providentially timed upstream landslide damming the waters of the Jordan at just the right time, similar to events which have actually occurred on the river several times in the past. On the other hand, the miracle at Jordan is compared to the miracle at the Red Sea (Joshua 4:23). This would suggest that it was also a true miracle of creation, involving the supernatural stabilizing of a wall of water until the crossing was completed.
3:16 from the city Adam. The towns of Adam and Zaretan were near the confluence of the rivers Jabbok and Jordan, some fifteen miles north of the Dead Sea. This long stretch of dry river bed provided ample room for the Israelites to cross over Jordan. This verse should be understood in the sense “an heap very far away, at the city Adam.”
3:17 passed clean over Jordan. In addition to this occasion, the Jordan was later stopped on two other occasions. See II Kings 2:8, 14. Only a small passageway was needed on these occasions for Elijah and Elisha to cross, but these also required God’s miraculous intervention.