Right, but what does that mean in the cultural context that produced the writing? In that culture, a man of higher social caste could strike one of lower caste on the left cheek, using the back of his left hand (the hand of "shame" making a statement of shame by the act of slapping). So, by "turning the cheek, the slapper would either have to 1) use his right hand to strike the left cheek (one didn't strike with the right hand), or 2) strike the right cheek (also unacceptable in that culture). The strikee isn't "resisting," he's simply making it very, very difficult for the striker without the striker acting shamefully. This is placing the passage squarely in the cultural context.