A rock, a particular rock, must be ripped out of its comfortable, familiar resting place in the mountainside. It must be separated from everything around it. It must be washed and scrubbed and moved hundreds or even thousands of miles away from where it was originally placed thousands of years ago.
It must be broken into unconnected pieces. It must be melted and tested and melted and tested and melted until the testing reveals that what remains is just the right quality for its purpose. Then it must be heated and rolled and pressed and mixed and cut and drilled and shaped and bent and twisted to become that one single piece that is needed to complete the grand design that was intended by the master builder.
It may be a rivet or a beam, a nail, a sheet, a screw, a nut or a cotter pin. It may be the protective shield over an entire structure or a small lever on the innermost sensitive micro switch. It is perfect. And all it took to get it there was a lifetime of work and planning and effort by untold numbers of people who cared that each piece of each rock from each mountain was molded and put to use according to the master planner.
You cannot be replaced. Without you it will not work. You are the most essential piece in God’s plan. You must be shaped into the piece He needs you to be.