Remember how the LORD your God led you all the way in the desert these forty years, to humble you and to test you in order to know what was in your heart, whether or not you would keep his commands. He humbled you, causing you to hunger and then feeding you with manna, which neither you nor your fathers had known, to teach you that man does not live on bread alone but by every word that comes from the mouth of the LORD. Your clothes did not wear out and your feet did not swell during these forty years. Know then in your heart that as a man disciplines his son, so the LORD your God disciplines you.
Like the Israelites, we are unaware of what lurks in the depths of our hearts. But if we are ever to be transformed in the wilderness, we need to know the true condition of our hearts. St. Macarius accurately and picturesquely describes the heart this way:
The heart itself is but a small vessel, yet dragons are there, and there are also lions; there are poisonous beasts and all the treasures of evil. But there too is God, the angels, the life and the kingdom, the light and the apostles, the heavenly cities and the treasuries of grace—all things are there. (H.43.7)
When wilderness testing unveils the condition of our hearts, we are humbled because we realize just how often we’re on the verge of denying Christ and worshiping idols. And we realize how completely dependent we are on God and his Word for every breath of grace-filled air.