Pour chicken broth into a 4-cup liquid measuring cup. Add water to measuring cup until the liquid measures 3 cups. Set aside.

Heat oil in a large saucepan over medium-high heat. Add garlic and cumin; cook for 30 seconds. Stir in rice. Add chicken broth and water mixture, salt, and pepper; bring to a boil. Reduce heat and simmer, covered, until rice is tender, about 20 minutes.

Stir in beans. Cover and heat until beans are hot, about 2 minutes more.