Albert Barnes Commentary Isaiah 41:20

"that they may see, and know, and consider, and understand together, that the hand of Jehovah hath done this, and the Holy One of Israel hath created it." — Isaiah 41:20 (ASV)

That they - The Jews, the people who shall be rescued from their long captivity, and restored to their own land. So rich and unexpected would be the blessings—as if in a pathless desert the most beautiful and refreshing trees and fountains would suddenly spring up—that they would have the fullest demonstration that they came from God.

Has created it - That is, all this is to be traced to him. In the apocryphal book of Baruch there is an expression concerning the return from Babylon remarkably similar to that used here by Isaiah: ‘Even the woods and every sweet-smelling tree shall overshadow Israel by the commandment of God’ (Isaiah 5:8).