"El ayuno según la Biblia: El ayuno es un arma poderosa de Dios para sus hijos" by Gonzalo Sanabria is a paperback book written in Spanish. It explores the biblical teachings on fasting as a powerful tool for spiritual growth and intimacy with God. With the author's expertise and faith-driven perspective, readers can gain a deeper understanding of the benefits and guidance on fasting in accordance with biblical principles. This book is a valuable resource for those looking to strengthen their spiritual connection through the practice of fasting as outlined in the Bible.