Charles Ellicott Commentary Joshua 15:4

"and it passed along to Azmon, and went out at the brook of Egypt; and the goings out of the border were at the sea: this shall be your south border." — Joshua 15:4 (ASV)

This shall be your south coast. —This phrase does not seem to fit in with the language of the rest of the passage.

However, it is strongly reminiscent of the language of Moses in Numbers 34:3, Numbers 34:6, Numbers 34:9, and Numbers 34:12. This book of the law shall not depart out of thy mouth was the instruction to Joshua, and in describing the border of Judah, he is really describing also the southern border of all Israel; and he does this throughout in language very similar to that of Moses in Numbers 34:0.

But Moses wrote it in the second person and in the future tense throughout; Joshua wrote it in the third person and in the past tense, with this one exception, in which he seems to have unconsciously adopted the phraseology of the lawgiver instead of the historian.