In a sermon a few years ago, Joseph Cardinal Ratzinger—now Pope Emeritus Benedict XVI—offered some insights about what it means to be “a true adult in the faith.” Reflecting on Ephesians 4.13–14, he said: “Being an ‘adult’ means having a faith which does not follow the waves of today’s fashions or the latest novelties. A faith which is deeply rooted in friendship with Christ is adult and mature.” Today’s Scripture reading is Mark 4.21–41. In it, Jesus shows us what it means to practice a mature, adult faith in him.

First, a mature Christian faith is characterized by openness. “For whatever is hidden is meant to be disclosed, and whatever is concealed is meant to be brought out into the open.” What should Christians be open about? About their faith, which is portrayed as a lamp lighting the way to salvation. “Do you bring in a lamp to put it under a bowl or a bed? Instead, don’t you put it on its stand?” Adult Christians do not hesitate to live their faith before others and share their faith with others. Why? Because they have nothing to hide.

Second, a mature Christian faith is characterized by mercy. “With the measure you use, it will be measured to you—and even more.” In other words, if you treat others judgmentally, you will be judged. If you treat others mercifully, you will receive mercy. “Whoever has will be given more; whoever does not have, even what he has will be taken away from him.” An adult Christian passes along to others the grace he has received from God.

Third, a mature Christian faith is oriented toward fruitfulness. Jesus tells two parables about the kingdom of God. The first one compares the kingdom to a farmer who scatters seed (vv. 26–29). “Night and day, whether he sleeps or gets up, the seed sprouts and grows…. As soon as the grain is ripe, he puts the sickle to it, because the harvest has come.” In other words, it is not enough that you make a good start in the faith. Seedliness is insufficient. God wants you to come to fruition, ready for the divine harvest of the resurrection.

Fourth, a mature Christian faith has influence. The second parable of the kingdom Jesus tells concerns “the mustard seed, which is the smallest seed you plant in the ground. Yet when planted, it grows and becomes the largest of all garden plants, with such big branches that the birds of the air can perch in its shade.” Does your Christianity provide help to others in need? Does it comfort mourners? Does it shelter victims?

Fifth, a mature Christian faith takes Christ at his word. In verses 35–41, Jesus and the disciples get into a boat to cross the Sea of Galilee. “Let us go over to the other side,” Jesus said. Midway through the journey, a storm arose that threatened to capsize the boat and drown them all. The disciples were anxious, but “Jesus was in the stern, sleeping on a cushion.” The disciples yelled at him: “Teacher, don’t you care if we drown.” Jesus woke up, calmed the storm, and questioned his disciples: “Why are you so afraid? Do you still have no faith?” When Jesus says, “Let us go over to the other side,” you will make it to the other side, no matter what happens along the way. A mature faith believes in Christ through troubled times.