Jim and Thelma Billings serve as Assemblies of God missionaries with the Latin American Advanced School of Theology (LAAST) where Jim is the current director.

LAAST is a training school for pastors and leaders of the 19 Spanish speaking nations in Latin America and the Caribbean that began as an answer to the many requests from national pastors for more theological training after Bible school. Since 1968 more than 1,000 Latin Americans have graduated from LAAST with the equivalent of a Bachelors Degree in Theology.

Jim and Thelma were missionariees to Bolivia, South America, for 26 years before joining LAAST ministry team in 2000. Before beginning their missionary career, Jim and Thelma pastored churches in Swisshome and Wallowa, Oregon.