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.