Commentaries:
Barnes' Notes
In the hills - See the Numbers 13:17 note.
The valleys - Or "the vale" (the Shephelah, Deuteronomy 1:7), which imports the lowland country between the mountains and the sea coast.
DISCLAIMER: Church of the Great God (CGG) provides these resources to aid the individual in studying the Bible. However, it is up to the individual to "prove all things, and hold fast to that which is good" (I Thessalonians 5:21). The content of these resources does not necessarily reflect the views of CGG. They are provided for information purposes only.