Water and Death: This concluding chapter of the middle section of the book suggests that the camp is ready to move again, but the events in chapter 20 delay any progress, and the loss of the exodus generation becomes more pressing with the deaths of two of its leaders. This chapter accounts for the exclusion of Moses and Aaron from the land. The movement of the wilderness generation is slow and painful, and frequently interrupted by trouble.
20:14–21 From Kadesh, Moses sends a diplomatic note to the ruler of Edom requesting passage toward Palestine. The form of the message was the common one of the day. The address speaks of your brother Israel. That is typical diplomatic language…
Baker Publishing Group, Understanding the Bible Commentary Series, by W.H. Bellinger, Jr.