My father drinks no water or milk, only Caffeine-Free Diet Pepsi. It's not my cup of tea, and I'm sure it's no good for the human organism, but he is 86 and out-walked me in Washington, D.C., last year, so I leave him alone.

My father is a feature in my backyard from April through October, peddling his bike here from home almost daily after his janitorial job, to put in his lettuces, cukes, and tomatoes. I reap the benefits and he asks for only Pepsi in exchange. But he is shy, you see, so all these years I have had to remember to holler out the back door and offer him the beverage, because he would never dream of walking in the house and opening the fridge.

I finally told him it would suit me better if he would help himself, but my son said I could just forget about that because "you can't teach an old dog new tricks." I would have mindlessly agreed to that bit of worldly wisdom except for the fact that two "old dogs" have been learning new tricks in the past year-my mother has turned from 79 years of rejecting Jesus to embracing him as her Savior and my father has risen to the occasion of my mother's illness and become a better husband in his 80s than he ever was in his 20s, 30s, 40s, 50s, 60s, and 70s. He takes her for walks; he does the laundry and grocery shopping. I guess the reader wouldn't know how astounding that is unless you had known him before.

So today when I heard my son use the expression "You can't teach an old dog new tricks," I called him on it. I have to call myself on it often too, as well as on many a worldly platitude I tend to spout automatically. Such expressions may seem harmless enough but they are actually little anti-gospels that, repeated over and over, bore into our souls and train us in the lies of hell, rather than the truths of God.