Ultimately the secret is perfect abandonment to the will of God in things you cannot control, and perfect obedience to Him in everything that depends on your own volition, so that in all things, in your interior life and in your outward works for God, you desire only one thing, which is the fulfillment of His will.
If you do this, your activity will share the disinterested peace that you are able to find at prayer, and in the simplicity of the things you do men will recognize your peacefulness and give glory to God...For the saint preaches sermons by the way he walks and the way he stands and the way he sits down and the way he picks things up and holds them in his hand.
There's not much to add here. The first sentence reminds me somewhat of what we know as the Serenity Prayer, which I've never been particularly fond of (purely for its popularity, I suspect). The last sentence, both by its structure and its content, is striking as well.