The "Subida" is the most significant work of the Church teacher of mysticism and serves as the gateway to all his later writings. Here, he primarily develops practically that radicalism which has attracted so many generous souls and determined their entire lives: "Give God (who is everything) what belongs to God, namely everything, and in this total surrender, commit yourselves to all that is God's kingdom in the world! The fire that burns here, which seems terrible and devastating to many who approach it for the first time, only seeks to take seriously the crucified love." In the preface to his work, John of the Cross writes: To say something about this dark night, I will not rely on experience and knowledge; ... rather, I will draw upon Holy Scripture in everything I wish to say with God's grace, under whose guidance we cannot err.