This is the quintessential song of oppression and persistence. Genuine faith rises to meet every challenge; against such faith persecution starves and withers. Given the context here, it would seem the threat is not some neighboring enemy, but internal enemies.
The first verse is dramatic repetition. Starting with the Exodus, Israel suffered from people seeking personal gain at the cost of the community. Israel has never been without internal opposition to God’s way; and such opposition has never prospered when their victims turn to God. We have the image of plowing with oxen to represent stripes of persecution. It’s the idea of trying to prosper from the suffering of others. Next comes the image of God cutting the reins used to pull the plow. Sooner or later the faithful will see God’s deliverance. The wicked will not harvest much.
Zion here is the symbol of God’s righteous rule and His blessings. There will always be predators seeking their own, but those who seek God will see the traitors thrown back. They’ll tuck their tails and run. These are people who are like the wild grass that infests patches of dirt blown into the corners of your roof. There’s not enough soil there. They sprout, but long before they can bear seed, they dehydrate. Nobody bothers to pick it for animal feed or bundle it into grass mats. You don’t even give them a ritual greeting; they are gone by the time you notice them.