My son (who did not get his green thumb from me) planted a Scotch thistle in his front yard just to see what it was like; it grew nearly two stories high, so striking with its pale, pale green leaves and purple blossoms that people driving by would stop, knock on the door and ask, “What is that?” My levelheaded daughter-in-law grew tired of answering the door to curious passers-by, and eventually got him to root the thistle out.

Like all parables, Jesus’ story of the mustard seed is double-edged. A mustard tree planted in a garden would grow aggressively and quickly take over; it is very difficult to root it out once that happens. The garden columnist in your local paper is likely to warn regularly what not to plant—usually, non-native species.

But the God who can “bring low the high tree, lift high the lowly tree, wither the green tree and make the withered tree bloom” can fill fearful human hearts with courage so strong that even persecution cannot root it out.

Marty Haugen’s beautifully simple setting of Henry Alford’s text—“We Walk By Faith,” (GIA)—is a natural for this Sunday, because it puts the phrase from the Second Reading into the context of how we are to live today. It’s usually sung rather lyrically, but invest the rhythm with energy—almost a march—and it can serve as a rousing closing song that reminds assembly members that we go forth with courage into the world and its dangers because we know we are under God’s protection.