Charles Ellicott Commentary Numbers 20:1

"And the children of Israel, even the whole congregation, came into the wilderness of Zin in the first month: and the people abode in Kadesh; and Miriam died there, and was buried there." — Numbers 20:1 (ASV)

Then came ... — It would be better to translate this way: And (or, Now) the children of Israel came (or, had come) ..., since the interval of time between the events related in the preceding chapters and this chapter is unknown.

In the first month.— It has been commonly supposed that the reference is to the first month of the fortieth year, when the Israelites are thought to have arrived for the second time at Kadesh. Some, however, are of the opinion that the journey is the same as that mentioned in Numbers 12:16 and Deuteronomy 1:19, and that the arrival at Kadesh was on the first month of the third year—that is, the year which followed the departure from Sinai. This departure took place on the twentieth day of the second month, in the second year after the exodus.

And the people stayed in Kadesh.— It is evident that the stay in Kadesh was an extended one, whether or not Kadesh served as the headquarters of the people from the second or third year of the exodus until they entered the land of Canaan. See Deuteronomy 1:46, where Moses describes the length of the stay in Kadesh by the words “many days,” the same words he uses in Numbers 20:15 to indicate the length of the stay in the land of Egypt.

It cannot, however, be inferred from the simple use of the word which is here rendered abode that the stay at Kadesh at the beginning of the fortieth year was long (see Judges 11:17, where the same word is used). Therefore, no valid conclusion can be drawn from the use of this word concerning whether the verse refers to an arrival at Kadesh at the beginning of the third or of the fortieth year after the exodus (see Numbers 20:14, and Note).