Gayle and Nancy Grisbee have served as Assemblies of God missionaries since 1982. They worked as general missionaries in Venezuela and the Dominican Republic, having been involved in lay leadership training, Bible School teaching and administration, as well as overseeing the construction of more than 70 churches

Since 2004 the Grisbees have worked with the Latin America Advanced School of Theology, where Gayle serves as a professor and Academic Dean and Nancy serves as Registrar. LAAST conducts 16-18 one-month long seminars throughout Latin America, training leaders as Bible School professors, administrators, missionaries, national executives and pastors. The program has over 2500 active students and more than 1500 graduates from its program, which began in 1968.