A couple weeks ago, I wrote a post about the Biblical sources for "Joy to the World." I thought that the lines "No more let sins and sorrows grow / Nor thorns infest the ground" came from the first part of Revelation 22. Revelation 22:2 mentions "the tree of life with its twelve kinds of fruits," and verse 3 says that "No longer will there be anything accursed." I thought these two things (an agricultural image and no more curses) were reworkt into these two lines in the hymn, yet I also felt I was missing something.
Earlier this week, I realized that this is a reference to Genesis 3:17-18 where God says to Adam, "Because you have listened to the voice of your wife and have eaten of the tree of which I commanded you, 'You shall not eat of it,' cursed is the ground because of you; in pain you shall eat of it all the days of your life; thorns and thistles it shall bring forth for you...." These are the "thorns" that are mentioned in "Joy to the World," and this is also "the curse" that's mentioned later in that verse: "He comes to make His blessings flow / Far as the curse is found."