keep (up) (one's) end of the bargain

To do as was promised in an agreement or bargain; to carry through with what one agreed to do. Also worded as "keep one's end of the bargain up." OK, I've delivered the cash as you instructed. Now you have to keep your end of the bargain! We've done the work on our end. I just hope their team keeps up their end of the bargain! My dad said he'd buy me a car if I got a 4.0 this semester, so I've got to ace this test if I want to keep my end of the bargain up.