In a large saucepan over medium-high heat, cook the bacon until crisp, about 3 minutes. Transfer the bacon to a piece of paper towel, and set aside. Discard all but 1 tablespoon bacon drippings from pan.
Add the garlic, onion, and carrots to saucepan. Cook vegetable mixture over medium heat until tender, about 5 minutes. Add the minced sage, and cook 1 minute more.
Add the lentils, cumin, and chicken stock; stir to combine. Simmer until lentils are cooked and falling apart, 20 to 25 minutes.
To serve, divide the hot soup among four soup plates, and garnish with the reserved bacon and additional sage.