A quick search of the online D-R Bible reveals that the Bible makes 40 references to thorns.
The first is in Genesis 3:18 after the fall.
And to Adam He said, '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 toil you shall eat of it all the days of your life: thorns and thistles it shall bring forth to you; and you shall eat the plants of the field. ....'
This sets the tone. I think it is important to note that God does NOT curse Adam or Eve at all. God explicitly says the serpent is cursed and the ground is cursed as a consequence of the fall but not humans. God says our lives will be difficult, we will have to toil and much of that toil may appear fruitless and/or be painful, but this is surely not a curse, it is a necessary chastisement so that we can come to know God better. And through Our Lord's willingness to embrace ALL the sorry consequences of the fall (though without any stain of sin Himself), ultimately our toil is elevated as a work of redemption and of glory. Indeed, if we too are willing to accept this toil for the love of God, especially where it is grossly unfair and not caused directly by our own sin, we can share in His work of redemption, because we are then in imitation of Him. And surely that is the lot of the saints.
But back to the thorns. The passage from Genesis seems to suggest that thorns and thistles are a consequence of the cursed ground. There would certainly be no thorns and no thistles in the Garden of Eden. They seem to be a part of God's creation that at best seems "useless" and at worst seem to be in direct conflict with the Tree of Life, strangling and blocking out all that is naturally good. However, I am not a fan of arguments about "usefulness". God doesn't seem to operate anywhere within the realms of "utility". Galaxies are too numerous to count and there are simply too many species of insects and plants most of which have yet to be discovered. Beauty in nature is fractal and spreads from the microscopic to the galactic with no diminishing is the lavishnes and abundance of its creativity. God is not interested in "usefulness". Love is not a "useful" thing, it simply is, it simply has being and simply propagates itself as and how it chooses because it can, and its "fecundity" would be unstopable if it weren't for sin. Thorns are not sin, God does not create sin.
So thorns then seem to strangle what is naturally good but they are God's work, therefore they MUST bring about grace if we accept them for what they are; a necessary chastisement a necessary block to our notions of progress and what is best for us, they spring up just when we don't want them, just when we think things are doing well, just when we forget God. So rejoice that we have been given thorns and rejoice that they are such a potent symbol of His plans for His stubborn, proud, little creatures.
How we should tackle the thorns that spring up in our lives will be the subject of my next post.