“he has cut the rope of the wicked.” The context is the wicked plowing upon the back of the righteous. God delivers the righteous by cutting the rope. Exactly what the “rope” refers to is unclear, but the general meaning of the verse is very clear: God delivers the righteous. It is possible that the “rope” is the rope that connected the oxen to the plow, or it could be the rope that connects the yoke to the oxen. It is even possible that verse 4 is not connected to verse 3 and that the “rope” refers to some other kind of oppressive rope. Concerning Jesus, the “rope” was things that bound him, and God cut that rope and fully delivered and then glorified him.
The wicked often succeed “upon the backs” of the righteous, in other words, by making the righteous work and toil, but God sets the captives free.