"The Catching Force"

There is a house of Missionaries of Charity sisters a few miles from where I live. Every morning after Mass, they pray the "Radiating Christ" prayer. It ends

"Stay with me and then I shall begin to shine as You shine, so to shine as to be a light to others; the light, O Jesus, will be all from You; none of it will be mine: it will be You shining on others through me. Let me thus praise You in the way You love best: by shining on those around me. Let me preach You without preaching, not by words, but by my example, by the catching force, the sympathetic influence of what I do, the evident fullness of the love my heart bears to You."

Office evangelization often includes this "preaching without preaching, but by example." In such circumstances, how can "the catching force" be animated? How can office work be done with "evident fullness" of love?