"Preach the gospel.  Use words if necessary." 
This is one of my husband's favorite quotes.  It is often attributed to St. Francis of Assisi, though while the origins of the thought are found in his teachings, the phrase "use words if necessary" do not even show up in his writings.  There is an interesting webpage describing the details that you can check for yourself by clicking here.  They claim that it doesn't even show until about 1996 during Msgr. homily during a funeral for Cardinal Bernardin...interesting.  But apparently it falls in with his teachings and philosophies pretty well?