In France last year I visited several rural Mass centers around Issoudun, the MSC place of foundation. I sat in each church for some time sensing the sacred and admiring the architecture that holds it, for many European churches sustain the sacred in the design of their arches, walls and vaults.
The keystone of main archways is one such example. The keystone enables the arch to be self-supporting. The scaffolding is taken away and the keystone will lock the arch in place. It will not move or fall so long as the keystone remains in place. In L’Aquila the place of the severe earthquake the arches stood while walls around fell.
When Jesus is the Keystone of your life there is an innate security for you. He holds you together. He enables you to feel self supported in your actions and your changing emotions. When the ground of your life shakes he gives stability and strength.