Isaiah 41:18

I will open rivers in high places, and fountains in the midst of the valleys: I will make the wilderness a pool of water, and the dry land springs of water.

I will open rivers ... I will make the wilderness a pool of water - alluding to the waters with which Israel was miraculously supplied in the desert after having come out of Egypt.

In high places - bare of trees, barren, and unwatered (; ).

In the midst of the valleys. "High places ... valleys" spiritually express that in all circumstances, whether elevated or depressed, God's people shall have refreshment for their souls, however little to be expected it might seem.