When Peter Welch was a young boy in the 1970s, using a metal detector was only a hobby. But since 1990, he’s been leading people from around the world on metal-detecting excursions. They’ve made thousands of discoveries—swords, ancient jewelry, coins. Using “Google Earth,” a computer program that renders a 3D representation of Earth based on satellite imagery, they look for patterns in the landscape on farmland in the United Kingdom. It shows them where roads, buildings, and other structures may have been centuries ago. Peter says, “To have a perspective from above opens a whole new world.”

God’s people in Isaiah’s…