Cover the beans with 2-3 inches of water. Bring the water to a boil, then reduce the heat so the water is barely simmering. Add the sage, partially cover and cook, stirring now and then, adding more water as needed. When the beans start to get tender, after maybe an hour but it really varies, add the salt and pepper.

Continue to cook at a low simmer until the beans are tender. (Just taste one.) If there's still lots of water, drain it. If there's just a bit, take the lid off the pot and let it evaporate. Stir in the garlic and olive oil, then serve.