For years, I thought that verse from the famous psalm was just beautiful poetry—David’s way of saying God was keeping him healthy, maybe keeping his mind strong. But I didn’t realize just how powerful that imagery is—until I learned what David, the shepherd boy-turned-king, was really pointing to.

In the Middle East, shepherds would take special care of their sheep. Because out in those dry fields and rocky hills, the danger wasn’t always a wolf or a lion. Sometimes, the greatest torment came from the smallest enemies—flies.