"Where's my money, honey?" From issue #9 of Luke's first ongoing: Doctor Doom has left town to avoid paying Luke $200. Luke does what any self-respecting hero for hire would do in these circumstances: he breaks into the Baxter Building, punches the Thing, convinces Reed Richards to lend him a plane, flies to Latveria, gets caught up in a robot rebellion led by an alien, and beats up Doom until he gets his money, and helps quash the rebellion. Luke gets his $200 and Dr. Doom's respect. Moral of the story: do not welch on Luke Cage.
Luke:(Grabbing Josten by the lapel) Before you go to sleep, little buttercup, I've got a few heavy words to lay on you. In the future, you may wish to take up this line of work again. Now, you can call yourself Spider-Man... you can call yourself the Invisible Woman... you can stick a flag in your navel and call yourself "The Spirit of '76"... but if you ever call yourself Power Man again... I will tattoo that name on your ribcage!(Turning to the crowd) Will one of you fine folks repeat that to the gentleman in the orange-and-brown suit when he wakes up?
In New Avengers, back before One More Day, the Avengers are having a training session. Upon Spidey attacking Wolverine, getting stabbed by him and explaining to everyone that Wolverine has been hitting on MJ, Luke simply turns to Wolverine and says this:
If what he says is true, I don't care what your bones are made of. They will break.
In the last issue of the 2013 run of Mighty Avengers, Luke's team tries and fails to stop the Deathwalkers from conducting a ritual that will merge them into a single, near-unstoppable being. Upon their union, the Deathwalkers force everyone in New York state to kneel in their direction at once, plunging them all into a custom-tailored illusion. Luke is the only one who is able to break free of it, and does so through sheer, stubborn refusal to quit.