When opportunities to send cards come up, I love to grab our book Gathered Gold by John Blanchard. This is a marvelous collection of quotes including numerous gems from the Puritans. Blanchard says he got a "trawling eye" after his conversion and began to gather quotes as he read. Today our oldest daughter turned 20, and I wrote this anonymous quote in her card: "If you wish to be disappointed, look to others; if you wish to be disheartened, look to yourself; if you wish to be encouraged, look to Jesus."
Another good quote is about evolution by G.K.Chesterton: "The evolutionist seem to know everything about the missing link except the fact that it is missing."