Paul, Peter, you, and I (and all of the Shepherd's sheep) are not left alone to figure out how to implement a one-time calling. Rather, we are called to daily intimacy where we listen to the voice that guides our every step.
Practically speaking, how do we engage in daily listening? By intentionally engaging in listening prayer. Carve out times of quiet, where you can ask God, "How do you want me to live out my calling today?" and then just listen, journaling any thoughts that come your way. Beyond time earmarked for prayer, as you go through your day, keep bringing that image of the Shepherd to mind. Pay attention to quiet whispers he murmurs in your heart, and try obeying them.
As we follow, listening, we are changed and transformed—and perhaps that is the point of calling: transformation.
In Buechner's wonderful essay "The Calling of Voices" (from his book The Hungering Dark), he wrote that the key to discerning calling is listening. A call is not something you do, it's something you hear. He wrote that voices all around us vie for our attention, attempting to direct us. "The more alive and alert we are, the more clamorous our lives are. Which do we listen to? What kind of voice do we listen for?" he asks. Because what we listen to shapes us. It transforms us, for better or worse.
He recommends that we listen to "the voice that we might think we should listen to least, and that is the voice of our own gladness." In other words, our calling often aligns with our spiritual gifts. God's gifting is part of how he speaks to us, if we have ears to hear.
As we listen to the voice of our own gladness (which ultimately comes from God and how he made us), I believe it is possible that God will shape us (and our gladness) into what he wants us to be. Calling has a certain fluidity to it, an elasticity. As we respond to God's calling, we are changed, stretched—and we find joy in tasks we might never have thought we could do before. Why? Because listening transforms our hearts. Calling is less about implementing a strategy on God's behalf, and more about how God is shaping our souls.
Have you ever listened to the voice of your own gladness? What do you love? What has God gifted you to do? As a busy leader, you may think you don't have time to think about that. But invest an hour in intentional solitude with God. Write down peak experiences, moments where you felt "deep gladness." What's the common denominator in these experiences? How do they align with what you are doing in your work or ministry? Ask God to speak to you through this exercise.