The U.S. Army didn’t invent that slogan. They stole it from God (Matthew 5:48)
Christians should be the most dedicated people in any function. The Saints understood this:
To be perfect in our vocation is nothing else than to fulfil the duties which our state of life obliges us to perform, and to accomplish them well, and only for the honor and love of God.
–St. Francis de Sales
h/t Suzanne at The Catholic Breadbox