From his forthcoming Center Church:

To illustrate what is needed for effective contextualization, let’s turn to the world of demolition. Say you are building a highway and want to remove a giant boulder. First, you drill a small shaft down into the center of the rock. Then you put explosives down the shaft into the core of the stone and detonate them. If you drill the shaft but never ignite the blast, you obviously will never move the boulder. But the same is true if you only blast and fail to drill—putting the explosives directly against the surface of
the rock. You will simply shear off the face of it, and the boulder will remain. All drilling with no blasting, or all blasting with no drilling, leads to failure. But if you do both of these, you will remove the rock.

To contextualize with balance and successfully reach people in a culture, we must both enter the culture sympathetically and respectfully (similar to drilling) and confront the culture where it contradicts biblical truth (similar to blasting).